Terminal device, communication method, and integrated circuit

ABSTRACT

There is provided a terminal device capable of efficiently performing communication in a communication system in which a base station device and the terminal device communicate with each other. The terminal device that communicates with the base station device by using a plurality of aggregated cells recognizes that a serving cell is stopped in a first state, recognizes that the serving cell is started in a second state, and switches from the first state to the second state based on a received PDCCH.

TECHNICAL FIELD

The present invention relates to a terminal device, a communicationmethod, and an integrated circuit.

BACKGROUND ART

A radio access scheme and a radio network for cellular mobilecommunication (hereinafter, referred to as “Long-Term Evolution (LTE)”or “Evolved Universal Terrestrial Radio Access: EUTRA”) have beenexamined in the 3rd Generation Partnership Project (3GPP). In the LTE, abase station device (base station) is also referred to as Evolved Node B(eNodeB), and a terminal device (mobile station, mobile station device,or terminal) is also referred to as user equipment (UE). The LTE is acellular communication system in which a plurality of areas within thecoverage of the base station device is arranged in the form of cells. Asingle base station device may manage a plurality of cells.

The LTE supports frequency-division duplexing (FDD) and time-divisionduplexing (TDD). The LTE that adopts the FDD system is also referred toas FD-LTE or LTE FDD. The TDD is a technology that enables full-duplexcommunication in at least two frequency bands by performingfrequency-division multiplexing on uplink signals and downlink signals.The LTE that adopts the TDD system is also referred to as TD-LTE or LTETDD. The TDD is a technology that enables full-duplex communication in asingle frequency band by performing time-division multiplexing on uplinksignals and downlink signals. The details of the FD-LTE and the TD-LTEare disclosed in NPL 1.

The base station device may transmit, to the terminal device, areference signal (referred to as RS) which is a known signal between thebase station device and the terminal device. As the reference signal, aplurality of reference signals may be transmitted for various purposessuch as demodulation of a signal channel or reporting of a channelstate. For example, a cell-specific reference signal is transmitted as areference signal specific to the cell in all downlink subframes. Forexample, a UE-specific reference signal is transmitted as a referencesignal specific to the terminal device in a resource to which a datasignal for the terminal device is mapped. The details of the referencesignals are disclosed in NPL 1.

In the 3GPP, the introduction of a small cell has been examined. Thesmall cell is the general term for cells of which a transmission powerof the base station device constituting this cell is low and coverage isnarrower than that of the cell (macrocell) of the related art. Forexample, since the small cell is applied in a high frequency band, it ispossible to arrange the small cells with high density, and an effect ofimproving frequency utilization efficiency per area is exhibited. In theexamination of the introduction of the small cell, a technology thatswitches the state of the base station device to a deactivated state hasbeen examined for various purposes such as low power consumption orinter-cell interference reduction. The details thereof are disclosed inNPL 2.

CITATION LIST Non Patent Literature

-   NPL 1: 3rd Generation Partnership Project; Technical Specification    Group Radio Access Network; Evolved Universal Terrestrial Radio    Access (E-UTRA); Physical Channels and Modulation (Release 11), 3GPP    TS 36.211 V11.5.0 (2014-01).-   NPL 2: 3rd Generation Partnership Project; Technical Specification    Group Radio Access Network; Small cell enhancements for E-UTRA and    E-UTRAN-Physical layer aspects (Release 12), 3GPP TR 36.872 V12.1.0    (2013-12).

SUMMARY OF INVENTION Technical Problem

However, in a case where the state of the base station device isswitched to the deactivated state, the transmission of thesynchronization signal or the reference signal is also stopped, and theterminal device is difficult to discover the base station device in thedeactivated state. In such a situation, since much preparation time isnecessary when the terminal device is connected to the base stationdevice in the deactivated state, transmission efficiency may be greatlydeteriorated.

The invention has been made in view of such problems, and it is anobject of the invention to provide a base station device, a terminaldevice, a communication system, a communication method and an integratedcircuit capable of improving transmission efficiency in a communicationsystem in which the base station device and the terminal devicecommunicate with each other.

Solution to Problem

In order to achieve the above-described object, the present inventionprovides the following means. That is, a terminal device according tothe present embodiment is a terminal device including: a detection unitthat detects a signal or a channel; and a channel measurement unit thatmeasures CSI based on a CSI reference resource defined by one validdownlink subframe. In a case where the signal or the channel is detectedin a subframe, it is expected that the subframe is the valid downlinksubframe.

A communication method according to the present embodiment is acommunication method of a terminal device. The method includes: a stepof detecting a signal or a channel; and a step of measuring CSI based ona CSI reference resource defined by one valid downlink subframe. In acase where the signal or the channel is detected in a subframe, it isexpected that the subframe is the valid downlink subframe.

An integrated circuit according to the present embodiment is anintegrated circuit mounted in a terminal device. The integrated circuitis adapted to have: a function of detecting a signal or a channel; and afunction of measuring CSI based on a CSI reference resource defined byone valid downlink subframe. In a case where the signal or the channelis detected in a subframe, it is expected that the subframe is the validdownlink subframe.

Advantageous Effects of Invention

According to the present invention, it is possible to improvetransmission efficiency in a wireless communication system in which abase station device and a terminal device communicate with each other.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a conceptual diagram of a wireless communication systemaccording to the present embodiment.

FIG. 2 is a diagram showing a schematic structure of a radio frameaccording to the present embodiment.

FIG. 3 is a diagram showing a structure of a slot according to thepresent embodiment.

FIG. 4 is a diagram showing an example of the arrangement of physicalchannels and physical signals in a downlink subframe according to thepresent embodiment.

FIG. 5 is a diagram showing an example of the arrangement of physicalchannels and physical signals in an uplink subframe according to thepresent embodiment.

FIG. 6 is a diagram showing an example of the arrangement of physicalchannels and physical signals in a special subframe according to thepresent embodiment.

FIG. 7 is a schematic block diagram showing a structure of a terminaldevice 1 according to the present embodiment.

FIG. 8 is a schematic block diagram showing a structure of a basestation device 3 according to the present embodiment.

FIG. 9 is a diagram showing an example of a structure of DRS.

FIG. 10 is a diagram showing an example of a structure of CRS and/or astructure of DRS.

FIG. 11 is a diagram showing another example of a structure of DRS.

FIG. 12 is a diagram showing an example of designation of a resourceelement in a configuration of DRS.

FIG. 13 is a diagram showing a measurement model.

FIG. 14 is a diagram showing an expression of a search space of PDCCHand EPDCCH.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described.

In the present embodiment, a plurality of cells may be configured for aterminal device 1. Here, a technology in which the terminal device 1communicates through a plurality of cells is referred to as cellaggregation, carrier aggregation, or dual connectivity. The presentinvention may be applied to each of the plurality of cells configuredfor the terminal device 1. The present invention may be applied to someof the plurality of configured cells. The cell configured for theterminal device 1 is referred to as a serving cell.

In the carrier aggregation (CA), the plurality of configured servingcells includes one primary cell (PCell), and one or a plurality ofsecondary cells (SCell).

The primary cell is a serving cell in which an initial connectionestablishment procedure is performed, a serving cell in which aconnection re-establishment procedure is started, or a cell indicated asa primary cell in a handover procedure. The primary cell is operated ata primary frequency. The secondary cell may be configured when or afterthe connection is (re)established. The secondary cell is operated at asecondary frequency. The connection may be referred to as RRCconnection.

One primary cell and one or more secondary cells are aggregated for theterminal device 1 that supports the CA.

The dual connectivity is an operation in which a certain terminal device1 consumes radio resources provided from at least two different networkpoints (a master base station device (MeNB: master eNB) and a secondarybase station device (SeNB: secondary eNB)). In other words, the dualconnectivity means that the terminal device 1 performs RRC connection inat least two network points. In the dual connectivity, the terminaldevice 1 may be connected in a RRC connection (RRC_CONNECTED) state andthrough non-ideal backhaul.

In the dual connectivity, a base station device 3 which is connected toat least S1-Mobility Management Entity (MME) and serves as mobilityanchor of a core network is referred to as a master base station devicein some cases. The base station device 3 that is not the master basestation device which provides additional radio resources to the terminaldevice 1 is referred to as a secondary base station device. A group ofserving cells associated with the master base station device is referredto as a master cell group (MCG) and a group of serving cells associatedwith the secondary base station device is referred to a secondary cellgroup (SCG) in some cases.

In the dual connectivity, the primary cell belongs to the MCG. In theSCG, a secondary cell corresponding to the primary cell is referred toas a primary secondary cell (pSCell). The pSCell is referred as aspecial cell or a special secondary cell (SCell) in some cases. Thespecial SCell (the base station device constituting the special SCell)may be supported by the same function (capability or performance) asthat of the PCell (a base station device constituting the PCell). Only apart of the function of the PCell may be supported by the pSCell. Forexample, the pSCell may be supported by a function of transmittingPDCCH. The pSCell may be supported by a function of performing the PDCCHtransmission by using a search space different from that of CSS or USS.For example, the search space different from that of the USS is a searchspace determined based on a value defined by the specification, or asearch space determined based on RNTI different from that of C-RNTI. ThepSCell may be constantly in an activated state. The pSCell is a cellcapable of receiving PUCCH.

In the dual connectivity, a radio bearer (data radio bearer (DRB) and/orsignalling radio bearer (SRB)) may be individually assigned in the MeNBand the SeNB.

In the dual connectivity, a duplex mode may be individually configuredin the MCG and the SCG, or the PCell and the pSCell.

In the dual connectivity, the MCG and the SCG, or the PCell and thepSCell may not be synchronized.

In the dual connectivity, a parameter (timing advance group: TAG) foradjusting a plurality of timings may be configured in each of the MCGand SCG (or the PCell and pSCell). That is, the MCG and the SCG may benot be synchronized.

In the dual connectivity, the terminal device 1 transmits UCIcorresponding to the cell within the MCG to only the MeNB (PCell), andtransmits UCI corresponding to the cell within the SCG to only the SeNB(pSCell). For example, the UCI is SR, HARQ-ACK, and/or CSI. In thetransmission of each UCI, a transmission method using the PUCCH and/orthe PUSCH is applied to each cell group.

All signals can be transmitted and received in the primary cell, butthere are signals that are not able to be transmitted and received inthe secondary cell. For example, physical uplink control channels(PUCCHs) are transmitted only in the primary cell. Physical randomaccess channels (PRACHs) are transmitted only in the primary cellbetween the cells as long as the plurality of timing advance groups(TAGs) is not configured. Physical broadcast channels (PBCHs) aretransmitted only in the primary cell. Master information blocks (MIB)are transmitted only on the primary cell.

In the primary secondary cell, the signals that can be transmitted andreceived in the primary cell are transmitted and received. For example,the PUCCHs may be transmitted in the primary secondary cell. The PRACHsmay be transmitted in the primary secondary cell irrespective of whetheror not the plurality of TAGs is configured. The PBCHs or the MIBs may betransmitted in the primary secondary cell.

Radio link failure (RLF) is detected in the primary cell. In thesecondary cell, even though a condition in which the RLF is detected issatisfied, it is not recognized that the RLF is detected. In the primarysecondary cell, if the condition is satisfied, the RLF is detected. Inthe primary secondary cell, in a case where the RLF is detected, ahigher layer of the primary secondary cell notifies a higher layer ofthe primary cell that the RLF is detected.

In the primary cell and/or the primary secondary cell, semi-persistentscheduling (SPS) or discontinuous transmission (DRX) may be performed.The total number of SPS configurations and DRX configurations may bedetermined by the total number of primary cells and primary secondarycells. In the secondary cell, the same DRX as that of the primary cellor the primary secondary cell of the same cell group may be performed.

In the secondary cell, information/parameters related to theconfigurations of the MAC are basically shared with the primary cell/theprimary secondary cell of the same cell group. A part (for example,sTAG-Id) of the parameters may be configured for each secondary cell.

A part of timers or counters may be applied to only the primary celland/or the primary secondary cell. The applied timer or counter may beconfigured for only the secondary cell.

A frame structure type of a frequency division duplex (FDD) or timedivision duplex (TDD) system is applied to a wireless communicationsystem according to the present embodiment. The frame structure type isreferred to as a frame format type or a duplex mode in some cases. Inthe case of the cell aggregation, the TDD system may be applied to allthe plurality of cells. In the case of the cell aggregation, the cellsto which the TDD system is applied and the cells to which the FDD systemis applied may be aggregated. In a case where the cells to which the TDDis applied and the cells to which the FDD is applied are aggregated, thepresent invention may be applied to the cells to which the TDD isapplied.

A half-duplex FDD system or a full-duplex FDD system may be applied tothe cells to which the FDD is applied.

In a case where the plurality of cells to which the TDD is applied isaggregated, a half-duplex TDD system or a full-duplex TDD system may beapplied.

The terminal device 1 transmits information indicating combinations ofbands in which the carrier aggregation is supported by the terminaldevice 1 to the base station device 3. The terminal device 1 transmitsinformation indicating whether or not each of the combinations of thebands supports simultaneous transmission and reception in the pluralityof serving cells in plurality of different bands to the base stationdevice 3.

In the present embodiment, “X/Y” includes the meaning of “X or Y”. Inthe present embodiment, “X/Y” includes the meaning of “X and Y”. In thepresent embodiment, “X/Y” includes the meaning of “X and/or Y”.

FIG. 1 is a conceptual diagram of the wireless communication systemaccording to the present embodiment. In FIG. 1, the wirelesscommunication system includes terminal devices 1A to 1C, and the basestation device 3. Hereinafter, the terminal devices 1A to 1C arereferred to as the terminal devices 1.

Physical channels and physical signals according to the presentembodiment will be described.

In FIG. 1, uplink physical channels are used in uplink wirelesscommunication from the terminal devices 1 to the base station device 3.The uplink physical channel may be used to transmit information outputfrom the higher layer. The uplink physical channel includes a physicaluplink control channel (PUCCH), a physical uplink shared channel(PUSCH), and a physical random access channel (PRACH).

The PUCCH is the physical channel used to transmit uplink controlinformation (UCI). The uplink control information includes channel stateinformation (CSI) of the downlink, scheduling request (SR) indicating arequest for a PUSCH resource, and acknowledgement(ACK)/negative-acknowledgement (NACK) of downlink data (transport block(TB) or downlink-shared channel (DL-SCH)). The ACK/NACK is also referredto as HARQ-ACK, HARQ feedback, or response information.

The PUSCH is the physical channel used to transmit uplink-shared channel(UL-SCH). The PUSCH may be used to transmit the HARQ-ACK and/or thechannel state information together with the uplink data. The PUSCH maybe used to transmit only the channel state information, or only theHARQ-ACK and the channel state information.

The PRACH is the physical channel used to transmit a random accesspreamble. The PRACH is mainly used by the terminal device 1 tosynchronize time domain with the base station device 3. In addition, thePRACH is used to indicate an initial connection establishment procedure,a handover procedure, a connection re-establishment procedure,synchronization (timing adjustment) of uplink transmission, and arequest for a PUSCH resource.

In FIG. 1, uplink physical signals are used in uplink wirelesscommunication. The uplink physical signal includes an uplink referencesignal (UL RS). As the uplink reference signal, a demodulation referencesignal (DMRS) and a sounding reference signal (SRS) are used. The DMRSis associated with the transmission of the PUSCH or the PUCCH. The DMRSis time-multiplexed with the PUSCH or the PUCCH. The base station device3 uses the DMRS in order to perform channel compensation of the PUSCH orthe PUCCH. Hereinafter, the transmission of both the PUSCH and the DMRSis simply referred to as the transmission of the PUSCH. Hereinafter, thetransmission of both of the PUCCH and the DMRS is simply referred to asthe transmission of the PUCCH. The DMRS of the uplink is also referredto as UL-DMRS. The SRS is not associated with the transmission of thePUSCH or the PUCCH. The base station device 3 uses the SRS in order tomeasure a channel state of the uplink.

As the SRS, there are two trigger types of SRSs (trigger type 0 SRS, andtrigger type 1 SRS). The trigger type 0 SRS is transmitted by higherlayer signalling in a case where a parameter related to the trigger type0 SRS is configured. The trigger type 1 SRS is transmitted by higherlayer signalling in a case where a parameter related to the trigger type1 SRS is configured and transmission is requested by a SRS requestincluded in DCI formats 0/1A/2B/2C/2D/4. The SRS request is included inboth the FDD and the TDD for the DCI formats 0/1A/4, and is includedonly in the TDD for the DCI formats 2B/2C/2D. In a case where thetransmission of the trigger type 0 SRS and the transmission of thetrigger type 1 SRS occur in the same subframe of the same serving cell,the transmission of the trigger type 1 SRS is prioritized.

In FIG. 1, downlink physical channels are used in downlink wirelesscommunication from the base station device 3 to the terminal device 1.The downlink physical channels are used to transmit information outputfrom the higher layer. The downlink physical channel includes a physicalbroadcast channel (PBCH), a physical control format indicator channel(PCFICH), a physical hybrid automatic repeat request indicator channel(PHICH), a physical downlink control channel (PDCCH), an enhancedphysical downlink control channel (EPDCCH), a physical downlink sharedchannel (PDSCH), and a physical multicast channel (PMCH).

The PBCH is used to broadcast a master information block (MIB, broadcastchannel (BCH)) which is commonly used in the terminal devices 1. The MIBmay be updated at an interval of 40 ms. The PBCH is repeatedlytransmitted at a cycle of 10 ms. Specifically, initial transmission ofthe MIB is performed in a subframe 0 in a radio frame that satisfies SFNmod 4=0, and repetition of the MIB in the subframe 0 in all other radioframes is performed. A system frame number (SFN) is a radio frame number(system frame number). The MIB is system information. For example, theMIB includes information indicating the SFN.

The PCFICH is used to transmit information indicating a region (OFDMsymbol) used to transmit the PDCCH.

The PHICH is used to transmit a HARQ indicator (HARQ feedback orresponse information) indicating the acknowledgement (ACK) or thenegative acknowledgement (NACK) of the uplink data (uplink sharedchannel (UL-SCH)) received by the base station device 3. For example, ina case where the terminal device 1 receives the HARQ indicatorindicating the ACK, the corresponding uplink data is not retransmitted.For example, in a case where the terminal device 1 receives the HARQindicator indicating the NACK, the corresponding uplink data isretransmitted. A single PHICH is used to transmit the HARQ indicatorcorresponding to single uplink data. The base station device 3respectively transmits HARQ indicators corresponding to a plurality ofuplink data items included in the same PUSCH by using a plurality ofPHICHs.

The PDCCH and the EPDCCH are used to transmit downlink controlinformation (DCI). The downlink control information is also referred toas a DCI format. The downlink control information includes a downlinkgrant and an uplink grant. The downlink grant is also referred to asdownlink assignment or downlink allocation.

The PDCCH is transmitted by the aggregation of one or a plurality ofsuccessive control channel elements (CCE). The CCE includes 9 resourceelement groups (REGs). The REG includes 4 resource elements. The PDCCHconstituted by n number of successive CCEs is started with a CCE thatsatisfies i mod n=0. Here, i is a CCE number.

The EPDCCH is transmitted by the aggregation of one or a plurality ofsuccessive enhanced control channel elements (ECCEs). The ECCE includesa plurality of enhanced resource element groups (EREGs).

The downlink grant is used in scheduling a single PDSCH within a singlecell. The downlink grant is used in scheduling a PDSCH within the samesubframe as a subframe in which the downlink grant is transmit. Theuplink grant is used in scheduling a single PUSCH within a single cell.The uplink grant is used in scheduling a single PUSCH within a subframewhich is positioned after four or more subframes from a subframe inwhich the uplink grant is transmitted.

A cyclic redundancy check (CRC) parity bit is added to the DCI format.The CRC parity bit is scrambled with a radio network temporaryidentifier (RNTI). The RNTI is an identifier capable of being defined orconfigured depending on the purpose of the DCI. The RNTI is anidentifier predefined in the specifications, an identifier configured asinformation specific to the cell, an identifier configured asinformation specific to the terminal device 1, or an identifierconfigured as information specific to a group belonging to the terminaldevices 1. For example, the CRC parity bit is scrambled with acell-radio network temporary identifier (C-RNTI), or a semi persistentscheduling cell-radio network temporary identifier (SPS C-RNTI). TheC-RNTI and the SPS C-RNTI are identifiers for identifying the terminaldevices 1 within the cell. The C-RNTI is used to control the PDSCH orthe PUSCH in a single subframe. The SPS C-RNTI is used to periodicallyassign a resource of the PDSCH or PUSCH.

The PDSCH is used to transmit a downlink shared channel (DL-SCH). ThePDSCH is used to transmit control information of the higher layer.

The PMCH is used to transmit multicast data (multicast channel (MCH)).

In FIG. 1, the following downlink physical signals are used in downlinkwireless communication. The downlink physical signal includes asynchronization signal (SS), and a downlink reference signal (DL RS).

The synchronization signal is used by the terminal device 1 tosynchronize the frequency domain and the time domain of the downlink.The synchronization signal is allocated to a predetermined subframewithin the radio frame. For example, in the TDD system, thesynchronization signals are allocated to subframes 0, 1, 5, and 6 withinthe radio frame. In the FDD system, the synchronization signals areallocated to the subframes 0 and 5 within the radio frame.

As the synchronization signal, there are a primary synchronizationsignal (PSS) and a secondary synchronization signal (SSS). The PSS isused to perform coarse frame/symbol timing synchronization(synchronization of the time domain) or to identify cell group. The SSSis used to more accurately perform frame timing synchronization and toidentify the cell. That is, the frame timing synchronization and thecell identification can be performed using the PSS and the SSS.

The downlink reference signal is used by the terminal device 1 toperform channel compensation of the downlink physical channel. Thedownlink reference signal is used by the terminal device 1 to calculatechannel state information of the downlink. The downlink reference signalis used by the terminal device 1 to measure a geographical position ofthe terminal device.

The downlink reference signal includes a cell-specific reference signal(CRS), a UE-specific reference signal (URS) associated with the PDSCH, ademodulation reference signal (DMRS) associated with the EPDCCH, anon-zero power channel state information-reference signal (NZP CSI-RS),a multimedia broadcast and multicast service over single frequencynetwork reference signal (MBSFN RS), a positioning reference signal(PRS), a new carrier type cell-specific reference signal (NCT CRS), anda discovery reference signal (DRS). The resource of the downlinkincludes a zero power channel state information-reference signal (ZPCSI-RS), and channel state information-interference measurement(CSI-IM).

The CRS is transmitted in all bands of the subframe. The CRS is used todemodulate the PBCH/PDCCH/PHICH/PCFICH/PDSCH. The CRS may be used by theterminal device 1 to calculate channel state information of thedownlink. The PBCH/PDCCH/PHICH/PCFICH is transmitted through an antennaport used to transmit the CRS.

The URS associated with the PDSCH is transmitted in the band and thesubframe used to transmit the PDSCH associated with the URS. The URS isused to demodulate the PDSCH with which the URS is associated.

The PDSCH is transmitted through an antenna port used to transmit theCRS or the URS based on a transmission mode and a DCI format. A DCIformat 1A is used to schedule the PDSCH transmitted through the antennaport used to transmit the CRS. A DCI format 2D is used to schedule thePDSCH transmitted through the antenna used to transmit the URS.

The DMRS associated with the EPDCCH is transmitted in the band and thesubframe used to transmit the EPDCCH with which the DMRS is associated.The DMRS is used to demodulate the EPDCCH with which the DMRS isassociated. The EPDCCH is transmitted through an antenna port used totransmit the DMRS.

The NZP CSI-RS is transmitted in the configured subframe. The resourcein which the NZP CSI-RS is transmitted is configured by the base stationdevice 3. The NZP CSI-RS is used by the terminal device 1 to calculatechannel state information of the downlink. The terminal device 1performs signal measurement (channel measurement) by using the NZPCSI-RS.

The resource of the ZP CSI-RS is configured by the base station device3. The base station device 3 transmits the ZP CSI-RS at zero power. Thatis, the base station device 3 does not transmit the ZP CSI-RS. The basestation device 3 does not transmit the PDSCH and the EPDCCH in theconfigured resource of the ZP CSI-RS.

The resource of the CSI-IM is configured by the base station device 3.The resource of the CSI-IM is configured so as to overlap a part of theresource of the ZP CSI-RS. That is, the resource of the CSI-IM has thesame characteristics as those of the ZP CSI-RS, and the base stationdevice 3 transmits the CSI-IM at zero power in the configured resource.That is, the base station device 3 does not transmit the CSI-IM. Thebase station device 3 does not transmit the PDSCH and the EPDCCH in theconfigured resource of the CSI-IM. The terminal device 1 may measureresource interference configured as the CSI-IM in the resourcecorresponding to the NZP CSI-RS in a certain cell.

As the channel state information (CSI), there are a channel qualityindicator (CQI), a precoding matrix indicator (PMI), a rank indicator(RI), and a precoding type indicator (PTI). The channel stateinformation is measured using the CSI-RS or the CRS.

The MBSFN RS is transmitted all the bands of the subframe used totransmit the PMCH. The MBSFN RS is used to demodulate the PMCH. The PMCHis transmitted through an antenna used to transmit the MBSFN RS.

The PRS is used by the terminal device 1 to measure the geographicalposition of the terminal device.

The NCT CRS may be mapped to a predetermined subframe. For example, theNCT CRS is mapped to the subframes 0 and 5. The NCT CRS may have thesame structure as that of a part of the CRS. For example, in eachresource block, the positions of the resource elements to which the NCTCRS is mapped may be the same as the positions of the resource elementsto which the CRS of the antenna port 0 is mapped. A sequence (value)used for the NCT CRS may be determined based on information configuredthrough the PBCH, PDCCH, EPDCCH or PDSCH (RRC signaling). A sequence(value) used for the NCT CRS may be determined based on a parameter suchas a cell ID (for example, a physical layer cell identity) or a slotnumber. A sequence (value) used for the NCT CRS may be determined by amethod (expression) different from a sequence (value) used for the CRSof the antenna port 0. The NCT CRS may be referred to as a trackingreference signal (TRS).

The downlink physical channel and the downlink physical signal aregenerically referred to as a downlink signal. The uplink physicalchannel and the uplink physical signal are generically referred to as anuplink signal. The downlink physical channel and the uplink physicalchannel are generically referred to as a physical channel. The downlinkphysical signal and the uplink physical signal are generically referredto as a physical signal.

The BCH, MCH, UL-SCH and DL-SCH are transport channels. A channel usedin a medium access control (MAC) layer is referred to as a transportchannel. A unit of the transport channel used in the MAC layer is alsoreferred to as a transport block (TB) or a MAC protocol data unit (PDU).Hybrid automatic repeat request (HARQ) is controlled for each transportblock in the MAC layer. The transport block is a unit of data which isdelivered to a physical layer by the MAC layer. In the physical layer,the transport block is mapped to a code word, and a coding process isperformed on each code word.

As a method of signaling (notifying and broadcasting) controlinformation to the terminal device 1 from the base station device 3,PDCCH signaling which is signaling through the PDCCH, RRC signalingwhich is signaling through the RRC layer, and MAC signaling which issignaling through the MAC layer are used. The RRC signaling is dedicatedRRC signaling for notifying of control information specific to theterminal device 1 or common RRC signaling for notifying of controlinformation specific to the base station device 3. In the followingdescription, in a case where the RRC signaling is simply described, theRRC signaling is the dedicated RRC signaling and/or the common RRCsignaling. The signaling, such as the RRC signaling or MAC CE, used in alayer higher than the physical layer is referred to as higher layersignalling.

Hereinafter, a structure of the radio frame according to the presentembodiment will be described.

FIG. 2 is a diagram showing a schematic structure of the radio frameaccording to the present embodiment. Each radio frame has a length of 10ms. Each radio frame includes two half frames. Each half frame has alength of 5 ms. Each half frame includes 5 subframes. Each subframe hasa length of 1 ms, and is defined by two successive slots. Each slot hasa length of 0.5 ms. An i-th subframe within the radio frame includes a(2×i)-th slot and a (2×i+1)-th slot. That is, each radio frame isdefined by 10 subframes.

The subframe includes a downlink subframe (first subframe), an uplinksubframe (second subframe), and a special subframe (third subframe).

The downlink subframe is a subframe reserved for downlink transmission.The uplink subframe is a subframe reserved for uplink transmission. Thespecial subframe includes three fields. The three fields are a downlinkpilot time slot (DwPTS), a guard period (GP), and an uplink pilot timeslot (UpPTS). The total length of the DwPTS, GP and UpPTS is 1 ms. TheDwPTS is a field reserved for downlink transmission. The UpPTS is afield reserved for uplink transmission. The GP is a field in which thedownlink transmission and the uplink transmission are not performed. Thespecial subframe may include only the DwPTS and the GP, or may includeonly the GP and the UpPTS. The special subframe is arranged between thedownlink subframe and the uplink subframe in the TDD, and is used toswitch the subframe from the downlink subframe to the uplink subframe.

A single radio frame includes the downlink subframe, the uplinksubframe, and/or the special subframe. That is, the radio frame mayinclude only the downlink subframe. The radio frame may include only theuplink subframe.

The wireless communication system according to the present embodimentsupports downlink-to-uplink switch-point periodicities of 5 ms and 10ms. In a case where the downlink-to-uplink switch-point periodicity is 5ms, the special subframes are included in both the half frames withinthe radio frame. In a case where the downlink-to-uplink switch-pointperiodicity is 10 ms, the special subframe is included only in aninitial half frame within the radio frame.

Hereinafter, a structure of the slot according to the present embodimentwill be described.

FIG. 3 is a diagram showing a structure of the slot according to thepresent embodiment. In the present embodiment, normal cyclic prefix (CP)is applied to an OFDM symbol. Extended cyclic prefix (CP) may be appliedto the OFDM symbol. The physical signal or the physical channeltransmitted in each slot is represented by a resource grid. In thedownlink, the resource grid is defined by a plurality of subcarriers ina frequency direction and a plurality of OFDM symbols in a timedirection. In the uplink, the resource grid is defined by a plurality ofsubcarriers in a frequency direction and a plurality of SC-FDMA symbolsin a time direction. The number of subcarriers or resource blocksdepends on a bandwidth of the cell. The number of OFDM symbols orSC-FDMA symbols constituting one slot is 7 in the case of the normal CPand is 6 in the case of the enhanced CP. Each element within theresource grid is referred to as a resource element. The resource elementis identified using a subcarrier number and an OFDM symbol or SC-FDMAsymbol number.

The resource block is used to be mapped to the resource element of acertain physical channel (PDSCH or PUSCH). The resource block is definedby a virtual resource block and a physical resource block. The certainphysical channel is initially mapped to by virtual resource block.Thereafter, the virtual resource block is mapped to the physicalresource block. One physical resource block is defined by 7 successiveOFDM symbols or SC-FDMA symbols in the time domain and 12 successivesubcarriers in the frequency domain. In addition, one physical resourceblock includes (7×12) number of resource elements. One physical resourceblock corresponds to one slot in the time domain, and corresponds to 180kHz in the frequency domain. Numbers from 0 are assigned to the physicalresource blocks in the frequency domain. Two resource blocks within onesubframe which correspond to the same physical resource block number aredefined as a physical resource block pair (PRB pair or RB pair).

Hereinafter, the physical channel and the physical signal transmitted ineach subframe will be described.

FIG. 4 is a diagram showing an example of the arrangement of thephysical channels and the physical signals in the downlink subframeaccording to the present embodiment. The base station device 3 maytransmit the downlink physical channel (PBCH, PCFICH, PHICH, PDCCH,EPDCCH, or PDSCH) and/or the downlink physical signal (synchronizationsignal or downlink reference signal) in the downlink subframe. The PBCHis transmitted only in the subframe 0 within the radio frame. Thedownlink reference signals are allocated to the resource elementsdistributed in the frequency domain and the time domain. In order tosimplify the description, the downlink reference signals are not shownin FIG. 4.

In PDCCH regions, a plurality of PDCCHs may be frequency-, time- and/orspatial-multiplexed. In EPDCCH regions, a plurality of EPDCCHs may befrequency-, time- and/or spatial-multiplexed. In PDSCH regions, aplurality of PDSCHs may be frequency-, time- and/or spatial-multiplexed.The PDCCHs, PDSCHs and/or EPDCCHs may be frequency-, time- and/orspatial-multiplexed.

FIG. 5 is a diagram showing an example of the arrangement of thephysical channels and the physical signals in the uplink subframeaccording to the present embodiment. The terminal device 1 may transmitthe uplink physical channel (PUCCH, PUSCH, or PRACH), and the uplinkphysical signal (UL-DMRS or SRS) in the uplink subframe. In PUCCHregions, a plurality of PUCCHs is frequency-, time-, spatial- and/orcode-multiplexed. In PUSCH regions, a plurality of PUSCHs may befrequency-, time-, spatial- and/or code-multiplexed. The PUCCHs and thePUSCHs may be frequency-, time-, spatial- and/or code-multiplexed. ThePRACH may be allocated to a single subframe or over two subframes. Aplurality of PRACHs may be code-multiplexed.

The SRS is transmitted using the last SC-FDMA symbol within the uplinksubframe. That is, the SRS is allocated to the last SC-FDMA symbolwithin the uplink subframe. The terminal device 1 may restrict thesimultaneous transmission of the SRS and the PUCCH/PUSCH/PRACH in asingle SC-FDMA symbol of a single cell. In a single uplink subframe of asingle cell, the terminal device 1 may transmit the PUSCH and/or thePUCCH by using the SC-FDMA symbol except for the last SC-FDMA symbolwithin the uplink subframe, and may transmit the SRS by using the lastSC-FDMA symbol within the uplink subframe. That is, the terminal device1 may transmit the SRS, the PUSCH and the PUCCH in a single uplinksubframe of a single cell. The DMRS is time-multiplexed with the PUCCHor the PUSCH. In order to simplify the description, the DMRS is notshown in FIG. 5.

FIG. 6 is a diagram showing an example of the arrangement of thephysical channels and the physical signals in the special subframeaccording to the present embodiment. In FIG. 6, the DwPTS includes firstto tenth SC-FDMA symbols within the special subframe, the GP includeseleventh and twelfth SC-FDMA symbols within the special subframe, andthe UpPTS includes thirteenth and fourteenth SC-FDMA symbols within thespecial subframe.

The base station device 3 may transmit the PCFICH, the PHICH, the PDCCH,the EPDCCH, the PDSCH, the synchronization signal, and the downlinkreference signal in the DwPTS of the special subframe. The base stationdevice 3 may restrict the transmission of the PBCH in the DwPTS of thespecial subframe. The terminal device 1 may transmit the PRACH and theSRS in the UpPTS of the special subframe. That is, the terminal device 1may restrict the transmission of the PUCCH, the PUSCH and the DMRS inthe UpPTS of the special subframe.

FIG. 7 is a schematic block diagram showing a structure of the terminaldevice 1 according to the present embodiment. As shown in the drawing,the terminal device 1 includes a higher layer processing unit 101, acontrol unit 103, a reception unit 105, a transmission unit 107, and atransmit and receive antenna 109. The higher layer processing unit 101includes a radio resource control unit 1011, a subframe configurationunit 1013, a scheduling information interpretation unit 1015, and achannel state information (CSI) report control unit 1017. The receptionunit 105 includes a decoding unit 1051, a demodulation unit 1053, ademultiplexing unit 1055, a wireless reception unit 1057, and a channelmeasurement unit 1059. The transmission unit 107 includes a coding unit1071, a modulation unit 1073, a multiplexing unit 1075, a wirelesstransmission unit 1077, and an uplink reference signal generation unit1079.

The higher layer processing unit 101 outputs uplink data (transportblock) generated through an operation of a user to the transmission unit107. The higher layer processing unit 101 performs processes of a mediumaccess control (MAC) layer, a packet data convergence protocol (PDCP)layer, a radio link control (RLC) layer and a radio resource control(RRC) layer. In a case where the carrier aggregation is performed, thehigher layer processing unit 101 has a function of controlling thephysical layer in order to perform the activation/deactivation of thecell, and a function of controlling the physical layer in order tomanage the transmission timing of the uplink. The higher layerprocessing unit 101 has a function of determining whether or not toinstruct the measurement to be calculated in the reception unit 105 andto report the measurement result calculated in the reception unit 105.

The radio resource control unit 1011 included in the higher layerprocessing unit 101 manages various configuration information items ofthe terminal device. The radio resource control unit 1011 generatesinformation allocated to each channel of the uplink, and outputs theallocated information to the transmission unit 107.

The subframe configuration unit 1013 included in the higher layerprocessing unit 101 manages a subframe configuration in the base stationdevice 3 and/or the base station device (for example, the base stationdevice 3A) different from the base station device 3 based on theinformation configured by the base station device 3. For example, thesubframe configuration is a configuration of the uplink or the downlinkfor the subframe. The subframe configuration includes a subframe patternconfiguration, an uplink-downlink configuration, an uplink referenceUL-DL configuration (uplink reference configuration), a downlinkreference UL-DL configuration (downlink reference configuration), and/ora transmission direction UL-DL configuration (transmission directionconfiguration). The subframe configuration unit 1013 sets the subframeconfiguration, the subframe pattern configuration, the uplink-downlinkconfiguration, the uplink reference UL-DL configuration, the downlinkreference UL-DL configuration, and/or the transmission direction UL-DLconfiguration. The subframe configuration unit 1013 may set at least twosubframe sets. The subframe pattern configuration includes an EPDCCHsubframe configuration. The subframe configuration unit 1013 is alsoreferred to as a terminal subframe configuration unit.

The scheduling information interpretation unit 1015 included in thehigher layer processing unit 101 interprets the DCI format (schedulinginformation) received through the reception unit 105, generates controlinformation in order to control the reception unit 105 and thetransmission unit 107 based on the result acquired by interpreting theDCI format, and outputs the generated control information to the controlunit 103.

The scheduling information interpretation unit 1015 determines timingswhen a transmission process and a reception process are performed basedon the subframe configuration, the subframe pattern configuration, theuplink-downlink configuration, the uplink reference UL-DL configuration,the downlink reference UL-DL configuration, and/or the transmissiondirection UL-DL configuration.

The CSI report control unit 1017 identifies a CSI reference resource.The CSI report control unit 1017 instructs the channel measurement unit1059 to derive a CQI associated with the CSI reference resource. The CSIreport control unit 1017 instructs the transmission unit 107 to transmitthe CQI. The CSI report control unit 1017 sets the configuration usedwhen the channel measurement unit 1059 calculates the CQI.

The control unit 103 generates control signals for controlling thereception unit 105 and the transmission unit 107 based on the controlinformation from the higher layer processing unit 101. The control unit103 outputs the generated control signals to the reception unit 105 andthe transmission unit 107, and controls the reception unit 105 and thetransmission unit 107.

The reception unit 105 separates, demodulates and decodes the receptionsignal received by the transmit and receive antenna 109 from the basestation device 3 based on the control signal input from the control unit103. The reception unit 105 outputs the decoded information to thehigher layer processing unit 101.

The wireless reception unit 1057 converts the downlink signal receivedby the transmit and receive antenna 109 into an intermediate frequency(performs down conversion), removes an unnecessary frequency components,controls an amplification level such that a signal level isappropriately maintained, performs orthogonal demodulation based onin-phase components and quadrature components of the received signal,and converts an analog signal acquired through the orthogonaldemodulation into a digital signal. The wireless reception unit 1057removes components equivalent to guard intervals (GIs) from theconverted digital signal, performs fast Fourier transform (FFT) on thesignal acquired by removing the guard intervals, and extracts a signalin the frequency domain.

The demultiplexing unit 1055 separates the extracted signal into thePHICH, the PDCCH, the EPDCCH, the PDSCH, and/or the downlink referencesignal. The demultiplexing unit 1055 compensates the channel of thePHICH, the PDCCH, the EPDCCH, and/or the PDSCH from an estimation valueof the channel input from the channel measurement unit 1059. Thedemultiplexing unit 1055 outputs the separated downlink reference signalto the channel measurement unit 1059.

The demodulation unit 1053 multiplies the PHICH by a corresponding codeto combine them, performs demodulation of a binary phase shift keying(BPSK) modulation scheme on the combined signal, and outputs thedemodulated signal to the decoding unit 1051. The decoding unit 1051decodes the PHICH addressed to the terminal device, and outputs thedecoded HARQ indicator to the higher layer processing unit 101. Thedemodulation unit 1053 performs modulation of a QPSK modulation schemeon the PDCCH and/or the EPDCCH, and outputs the demodulated PDCCH and/orthe EPDCCH to the decoding unit 1051. The decoding unit 1051 tries todecode the PDCCH and/or the EPDCCH, and outputs the decoded downlinkcontrol information and the RNTI corresponding to the downlink controlinformation to the higher layer processing unit 101 in a case where thedecoding succeeds.

The demodulation unit 1053 performs demodulation of a modulation scheme,such as quadrature phase shift keying (QPSK), 16 quadrature amplitudemodulation (QAM), 64-QAM, which is notified through the downlink grant,on the PDSCH, and outputs the demodulated PDSCH to the decoding unit1051. The decoding unit 1051 performs decoding based on informationrelated to a coding rate notified through the downlink controlinformation, and outputs the decoded downlink data (transport block) tothe higher layer processing unit 101.

The channel measurement unit 1059 measures a path loss of the downlinkor a state of the channel from the downlink reference signal input fromthe demultiplexing unit 1055, and outputs the measured path loss andchannel state to the higher layer processing unit 101. The channelmeasurement unit 1059 calculates an estimation value of the channel ofthe downlink from the downlink reference signal, and outputs theestimation value to the demultiplexing unit 1055. In order to calculatethe CQI, the channel measurement unit 1059 performs channel measurementand/or interference measurement. The channel measurement unit 1059performs measurement for notifying the higher layer from the downlinkreference signal input from the demultiplexing unit 1055. The channelmeasurement unit 1059 calculates the RSRP and the RSRQ, and outputs thecalculated RSRP and RSRQ to the higher layer processing unit 101.

According to the control signal input from the control unit 103, thetransmission unit 107 generates the uplink reference signal, codes andmodulates the uplink data (transport block) input from the higher layerprocessing unit 101, multiplexes the PUCCH, the PUSCH, and the generateduplink reference signal, and transmits the multiplexed signal to thebase station device 3 through the transmit and receive antenna 109.

The coding unit 1071 performs coding such as convolutional coding orblock coding on the uplink control information input from the higherlayer processing unit 101. The coding unit 1071 performs turbo codingbased on information used in scheduling the PUSCH.

The modulation unit 1073 modulates coding bits input from the codingunit 1071 by using a modulation scheme, such as BPSK, QPSK, 16-QAM or64-QAM, which is notified through the downlink control information, or amodulation scheme previously determined for each channel. The modulationunit 1073 determines the number of sequences of data which isspatial-multiplexed based on the information used in scheduling thePUSCH, maps a plurality of uplink data items transmitted through thesame PUSCH by using multiple input multiple output spatial multiplexing(MIMO SM) to a plurality of sequences, and performs precoding on thesequences.

The uplink reference signal generation unit 1079 generates a sequenceacquired by a predetermined rule (expression) based on physical layercell identity (PCI) (referred to as Cell ID) for identifying the basestation device 3, a bandwidth to which the uplink reference signal isallocated, a cyclic shift notified through the uplink grant, and aparameter value for generating a DMRS sequence. According to the controlsignal input from the control unit 103, the multiplexing unit 1075rearranges the modulation symbols of the PUSCH in parallel, and thenperforms discrete Fourier transform (DFT). The multiplexing unit 1075multiplexes the PUCCH and PUSCH signals and the generated uplinkreference signal for each transmit antenna port. That is, themultiplexing unit 1075 arranges the PUCCH and PUSCH signals and thegenerated uplink reference signal in the resource elements for eachtransmit antenna port.

The wireless transmission unit 1077 performs inverse fast Fouriertransform (IFFT) on the multiplexed signal, performs modulation of aSC-FDMA scheme, adds the guard intervals to the SC-FDMA symbols acquiredthrough the SC-FDMA modulation, and generates a baseband digital signal.The wireless transmission unit converts the baseband digital signal intoan analog signal, generates in-phase components and quadraturecomponents of the intermediate frequency from the analog signal, removesexcessive frequency components in the intermediate frequency band,converts the signal having the intermediate frequency into a signalhaving a high frequency (performs up conversion), and removes excessivefrequency components. The transmission unit amplifies power, and outputsand transmits the amplified signal to the transmit and receive antenna109.

FIG. 8 is a schematic block diagram showing a structure of the basestation device 3 according to the present embodiment. As shown in thedrawing, the base station device 3 includes a higher layer processingunit 301, a control unit 303, a reception unit 305, a transmission unit307, and a transmit and receive antenna 309. The higher layer processingunit 301 includes a radio resource control unit 3011, a subframeconfiguration unit 3013, a scheduling unit 3015, and a CSI reportcontrol unit 3017. The reception unit 305 includes a decoding unit 3051,a demodulation unit 3053, a demultiplexing unit 3055, a wirelessreception unit 3057, and a channel measurement unit 3059. Thetransmission unit 307 includes a coding unit 3071, a modulation unit3073, a multiplexing unit 3075, a wireless transmission unit 3077, and adownlink reference signal generation unit 3079.

The higher layer processing unit 301 performs the processes of themedium access control (MAC) layer, the packet data convergence protocol(PDCP) layer, the radio link control (RLC) layer and the radio resourcecontrol (RRC) layer. The higher layer processing unit 301 generatescontrol information in order to control the reception unit 305 and thetransmission unit 307, and outputs the generated control information tothe control unit 303. The higher layer processing unit 301 having afunction of acquiring the reported measurement result.

The radio resource control unit 3011 included in the higher layerprocessing unit 301 generates downlink data (transport block), systeminformation, RRC message or MAC control element (CE) which is allocatedto the PDSCH of the downlink or acquires the information from a highernode, and outputs the generated or acquired information to thetransmission unit 307. The radio resource control unit 3011 managesvarious configuration information items of each terminal device 1.

The subframe configuration unit 3013 included in the higher layerprocessing unit 301 manages the subframe configuration, the subframepattern configuration, the uplink-downlink configuration, the uplinkreference UL-DL configuration, the downlink reference UL-DLconfiguration, and/or the transmission direction UL-DL configuration foreach terminal device 1. The subframe configuration unit 3013 sets thesubframe configuration, the subframe pattern configuration, theuplink-downlink configuration, the uplink reference UL-DL configuration,the downlink reference UL-DL configuration, and/or the transmissiondirection UL-DL configuration for each terminal device 1. The subframeconfiguration unit 3013 transmits information related to the subframeconfiguration to the terminal device 1. The subframe configuration unit3013 is also referred to as a base station subframe configuration unit.

The base station device 3 may determine the subframe configuration, thesubframe pattern configuration, the uplink-downlink configuration, theuplink reference UL-DL configuration, the downlink reference UL-DLconfiguration, and/or the transmission direction UL-DL configuration forthe terminal device 1. The base station device 3 may determine thesubframe configuration, the subframe pattern configuration, theuplink-downlink configuration, the uplink reference UL-DL configuration,the downlink reference UL-DL configuration, and/or the transmissiondirection UL-DL configuration for the terminal device 1 according to theindication from the higher node.

For example, the subframe configuration unit 3013 may determine thesubframe configuration, the subframe pattern configuration, theuplink-downlink configuration, the uplink reference UL-DL configuration,the downlink reference UL-DL configuration, and/or the transmissiondirection UL-DL configuration based on a traffic amount of the uplinkand a traffic amount of the downlink.

The subframe configuration unit 3013 may manage at least two subframesets. The subframe configuration unit 3013 may set at least two subframesets to each terminal device 1. The subframe configuration unit 3013 mayset at least two subframe sets to each serving cell. The subframeconfiguration unit 3013 may set at least two subframe sets to each CSIprocess. The subframe configuration unit 3013 may transmit informationindicating at least two subframe sets to the terminal device 1 throughthe transmission unit 307.

The scheduling unit 3015 included in the higher layer processing unit301 determines subframes and frequencies to which the physical channels(PDSCH and PUSCH) are assigned, coding rates of the physical channels(PDSCH and PUSCH), a modulation scheme, and a transmission power fromthe received channel state information and the estimation value of thechannel or the quality of the channel input from the channel measurementunit 3059. The scheduling unit 3015 determines whether to schedule thedownlink physical channel and/or the downlink physical signal or theuplink physical channel and/or the uplink physical signal in theflexible subframe. The scheduling unit 3015 generates controlinformation (for example, DCI format) in order to control the receptionunit 305 and the transmission unit 307 based on the scheduling result,and outputs the generated control information to the control unit 303.

The scheduling unit 3015 generates information used in scheduling thephysical channels (PDSCH and PUSCH) based on the scheduling result. Thescheduling unit 3015 determines timings (subframes) when thetransmission process and the reception process are performed based onthe UL-DL configuration, the subframe pattern configuration, theuplink-downlink configuration, the uplink reference UL-DL configuration,the downlink reference UL-DL configuration, and/or the transmissiondirection UL-DL configuration.

The CSI report control unit 3017 included in the higher layer processingunit 301 controls the CSI report of the terminal device 1. The CSIreport control unit 3017 transmits information indicating variousconfigurations assumed in order to cause the terminal device 1 to derivethe CQI in the CSI reference resource to the terminal device 1 throughthe transmission unit 307.

The control unit 303 generates control signals for controlling thereception unit 305 and the transmission unit 307 based on the controlinformation from the higher layer processing unit 301. The control unit303 outputs the generated control signals to the reception unit 305 andthe transmission unit 307 to control the reception unit 305 and thetransmission unit 307.

The reception unit 305 separates, demodulates, and decodes the receptionsignal received from the terminal device 1 through the transmit andreceive antenna 309 according to the control signal input from thecontrol unit 303, and outputs the decoded information to the higherlayer processing unit 301. The wireless reception unit 3057 converts theuplink signal received through the transmit and receive antenna 309 intoan intermediate frequency (performs down conversion), removesunnecessary frequency components, controls an amplification level suchthat a signal level is approximately maintained, performs orthogonaldemodulation based on the in-phase components and quadrature componentsof the received signal, and converts an analog signal acquired throughthe orthogonal demodulation into a digital signal.

The wireless reception unit 3057 removes components equivalent to guardintervals (GIs) from the converted digital signal. The wirelessreception unit 3057 performs fast Fourier transform (FFT) on the signalacquired by removing the guard intervals, extracts the signal in thefrequency domain, and outputs the extracted signal to the demultiplexingunit 3055.

The demultiplexing unit 1055 separates the signal input from thewireless reception unit 3057 into signals such as the PUCCH, the PUSCHand the uplink reference signal. The demultiplexing is performed basedon assignment information of a radio resource which is previouslydetermined by the radio resource control unit 3011 of the base stationdevice 3 and is included in the uplink grant notified to each terminaldevice 1. The demultiplexing unit 3055 compensates the channels of thePUCCH and the PUSCH from the estimation value of the channel input fromthe channel measurement unit 3059. The demultiplexing unit 3055 outputsthe separated uplink reference signal to the channel measurement unit3059.

The demodulation unit 3053 performs inverse discrete Fourier transform(IDFT) on the PUSCH, acquires the modulation symbols, and demodulatesthe reception signal for the modulation symbols of the PUCCH and thePUSCH by using a modulation scheme, such as binary phase shift keying(BPSK), QPSK, 16-QAM or 64-QAM, which is previously determined orpreviously notified through the uplink grant to each terminal device 1from the base station device. The demodulation unit 3053 separates themodulation symbols of a plurality of uplink data items transmittedthrough the same PUSCH by using the MIMO SM based on the number ofsequences which are previously notified through the uplink grant to eachterminal device 1 and are spatial-multiplexed, and the informationindicating that precoding is performed on the sequences.

The decoding unit 3051 performs decoding on coding bits of thedemodulated PUCCH and PUSCH by a predetermined coding scheme at a codingrate which is previously determined or is previously notified to theterminal device 1 from the base station device through the uplink grant,and outputs the decoded uplink data and the uplink control informationto the higher layer processing unit 101. In a case whether the PUSCH isretransmitted, the decoding unit 3051 performs decoding by using codingbits which are input from the higher layer processing unit 301 and areretained in a HARQ buffer and the demodulated coding bits. The channelmeasurement unit 309 measures the estimation value of the channel or thequality of the channel from the uplink reference signal input from thedemultiplexing unit 3055, and outputs the measured result to thedemultiplexing unit 3055 and the higher layer processing unit 301.

The transmission unit 307 generates the downlink reference signalaccording to the control signal input from the control unit 303, codesand modulates the HARQ indicator, the downlink control information andthe downlink data input from the higher layer processing unit 301,multiplexes the PHICH, the PDCCH, the EPDCCH, the PDSCH, and thedownlink reference signal, and transmits the signal to the terminaldevice 1 through the transmit and receive antenna 309.

The coding unit 3071 performs coding on the HARQ indicator, the downlinkcontrol information and the downlink data input from the higher layerprocessing unit 301 by using a predetermined coding scheme such as blockcoding, convolutional coding or turbo coding, or performs coding byusing a coding scheme determined by the radio resource control unit3011. The modulation unit 3073 modulates the coding bits input from thecoding unit 3071 by using a modulation scheme, such as BPSK, QPSK,16-QAM or 64-QAM, which is previously determined or is determined by theradio resource control unit 3011.

The downlink reference signal generation unit 3079 generates a sequencewhich is acquired by a predetermined rule based on the physical layercell identity (PCI) for identifying the base station device 3 and isknown to the terminal device 1, as the downlink reference signal. Themultiplexing unit 3075 multiplexes the modulation symbols of eachmodulated channel and the generated downlink reference signal. That is,the multiplexing unit 3075 arranges the modulation symbols of eachmodulated channel and the generated downlink reference signal in theresource elements.

The wireless transmission unit 3077 performs inverse fast Fouriertransform (IFFT) on the multiplexed modulation symbols, performsmodulation of an OFDM scheme, adds the guard intervals to the OFDMsymbols acquired through the OFDM modulation, and generates a basebanddigital signal. The wireless transmission unit converts the basebanddigital signal into an analog signal, generates in-phase components andquadrature components of the intermediate frequency from the analogsignal, removes excessive frequency components in the intermediatefrequency band, converts the signal having the intermediate frequencyinto a signal having a high frequency (performs up conversion), andremoves excessive frequency components. The transmission unit amplifiespower, and outputs and transmits the amplified signal to the transmitand receive antenna 309.

Here, the PDCCH or the EPDCCH is used to notify (designate) the terminaldevice of the downlink control information (DCI). For example, thedownlink control information includes information related to resourceassignment of the PDSCH, information related to a modulation and codingscheme (MCS), information related to scheduling identity (also referredto as a scheduling identifier), and information related to a referencesignal sequence identity (also referred to as base sequence identity,base sequence identifier, or base sequence index).

Hereinafter, a small cell will be described.

The small cell is the general term for cells which are constituted bythe base station device 3 having a transmission power lower than that ofa macrocell and have narrow coverage. Since the small cell can beconfigured to have narrow coverage, the small cells can be operated bybeing densely arranged. The base station device 3 as the small cell isarranged in a place different from the base station device as themacrocell. The densely arranged small cells may be synchronized witheach other, and may be provided as a small cell cluster. The small cellswithin the small cell cluster may be connected through backhaul (opticalfiber, X2 interface or S1 interface), and an interference suppressiontechnique such as enhanced Inter-Cell Interference Coordination (eICIC),Further enhanced Inter-cell Interference Coordination (FeICIC), orCoordinated Multi-point transmission/reception (CoMP) may be applied inthe small cells within the small cell cluster. The small cell may beoperated in a frequency band different from that of the macrocell, ormay be operated in the same frequency band as that of the macrocell.Particularly, in view of channel attenuation (path loss), it is possibleto easily allow the small cell to have narrower coverage by operatingthe small cell in a frequency band higher than that of the macrocell.

The small cell operated in the different frequency band is operatedusing the macrocell and the carrier aggregation technology or the dualconnectivity technology.

The small cell may be operated in the same frequency as that of themacrocell. The small cell may be operated out of the coverage of themacrocell. The base station device 3 as the small cell may be arrangedin the same place as that of the base station device as the macrocell.

The base station device 3 recognizes whether a certain cell is themacrocell or the small cell, and terminal device 1 does not need torecognize whether a certain cell is the macrocell or the small cell. Forexample, the base station device 3 may configure the macrocell as thePcell may configure the small cell as the Scell or the pSCell for theterminal device 1. In any case, the terminal device 1 may recognize acertain cell as the PCell, the SCell or the pSCell, and does not need torecognize a certain cell as the macrocell or the small cell.

Hereinafter, the details of the carrier aggregation technology and thedual connectivity technology will be described.

The secondary cell may be configured such that the secondary cell andthe primary cell constitute a set of serving cells depending on thecapability (performance and function) of the terminal device 1. Thenumber of downlink component carriers configured for the terminal device1 needs to be equal to or greater than the number of uplink componentcarriers configured for the terminal device 1, and only the uplinkcomponent carriers are not able to be configured as the secondary cells.

The terminal device 1 uses constantly the primary cell and the primarysecondary cell for transmitting the PUCCHs. In other words, the terminaldevice 1 does not expect to transmit the PUCCH in the secondary cellother than the primary cell and the primary secondary cell.

The reconfiguration/addition/removal of the secondary cell is performedby the RRC. When a new secondary cell is added, all system informationitems required by the new secondary cell are transmitted through thededicated RRC signaling. That is, it is not necessary to directlyacquire the system information from the secondary cell through thebroadcasting in an RRC connected mode.

When the carrier aggregation is configured, the mechanism of theactivation/deactivation of the secondary cell is supported. Theactivation/deactivation is not applied to the primary cell. When thesecondary cell is deactivated, the terminal device 1 does not need toreceive the associated PDCCH or PDSCH, is not able to perform thetransmission in the associated uplink, and does not need to perform CQImeasurement. In contrast, when the secondary cell is activated, sincethe terminal device 1 receives the PDSCH and the PDCCH, it is expectedthat the CQI measurement can be performed.

The mechanism of the activation/deactivation is based on the combinationof the MAC CE and a deactivation timer. The MAC CE notifies ofinformation of the activation and the deactivation of the secondary cellas a bitmap. A bit set to be 1 indicates the activation of theassociated secondary cell, and a bit set to be 0 indicates thedeactivation of the associated secondary cell.

The deactivation as an initial state is configured for the secondarycell configured for the terminal device 1. That is, even though variousparameters for the secondary cell are configured for the terminal device1, the communication may or may not be immediately performed using thesecondary cell.

Hereinafter, an example of the MAC CE will be described.

An example of a structure of the activation/deactivation MAC CE will bedescribed. The MAC CE has a fixed size, and includes seven Ci fields andone R field. The MAC CE is defined as follows. As for the Ci, in a casewhere there is the secondary cell for which a secondary cell index(SCellIndex) i is configured, the Ci field indicates a state of theactivation/deactivation of the secondary cell accompanying by thesecondary cell index i. In a case where there is no secondary cell forwhich the secondary cell index i is configured, the terminal device 1ignores the Ci field. A case where the Ci field is set to be “1” meansthat the secondary cell accompanying by the secondary cell index i isactivated. A case where the Ci field is set to be “0” means that thesecondary cell accompanying by the secondary cell index i isdeactivated. The R is a reserved bit, and is set to be “0”.

Hereinafter, an example of the deactivation timer for the secondary cellwill be described.

In a case where the deactivation timer is configured for the secondarycell, the deactivation timer is a timer associated with a maintainingtime of the secondary cell. The terminal device 1 retains thedeactivation timer for each secondary cell, and deactivates thesecondary cell associated with the expired deactivation timer if thedeactivation timer expires.

An initial value of the deactivation timer for the secondary cell isconfigured using a parameter sCellDeactivationTimer-r10 from the higherlayer (RRC layer). For example, one of rf2, rf4, rf8, rf16, rf32, rf64and rf128 which are values associated with the number of radio frames isconfigured for the initial value of the deactivation timer for thesecondary cell. Here, the rf2 corresponds to 2 radio frames, the rf4corresponds to 4 radio frames, the rf8 corresponds to 8 radio frames,the rf16 corresponds to 16 radio frames, the rf32 corresponds to 32radio frames, the rf64 corresponds to 64 radio frames, and the rf128corresponds to 128 radio frames.

The field (parameter sCellDeactivationTimer-r10) associated with thedeactivation timer for the secondary cell is configured for only theterminal device 1 for which one or more secondary cells are configured.

In a case where there is no field associated with the deactivationtimer, it is assumed that the terminal device 1 removes an existingvalue of the field associated with the deactivation timer and aninfinity value is configured.

In a case where only one field associated with the deactivation timerfor the secondary cell is configured for the terminal device 1, the sameinitial value of the deactivation timer is adapted to each secondarycell (a function associated with the deactivation timer is independentlyperformed in each secondary cell).

An example of the mechanism of the activation/deactivation will bedescribed.

In a case where the MAC CE indicating the activation of the secondarycell is received, the terminal device 1 configures the secondary cellfor which the activation is configured by the MAC CE as activation.Here, the terminal device 1 may perform the following operation on thesecondary cell for which the activation is configured by the MAC CE.This operation includes the transmission of the SRS in the secondarycell, the reporting of the channel quality indicator (CQI)/precodingmatrix indicator (PMI)/rank indicator (RI)/precoding type indicator(PTI) for the secondary cell, the transmission of the uplink data(UL-SCH) in the secondary cell, the transmission of the RACH in thesecondary cell, the monitoring of the PDCCH in the secondary cell, andthe monitoring of the PDCCH for the secondary cell.

In a case where the MAC CE indicating the activation of the secondarycell is received, the terminal device 1 starts or restarts thedeactivation timer associated with the secondary cell for which theactivation is configured by the MAC CE. The starting means that thetimer which retains the value starts to count. The restarting means thatthe value is configured as the initial value and the timer restarts tocount.

In a case where the MAC CE indicating the activation of the secondarycell is received, the terminal device 1 triggers the transmission of aremaining power of the transmission power (power head room (PHR)).

In a case where the MAC CE indicating the deactivation of the secondarycell is received, or in a case where the deactivation timer associatedwith the secondary cell expires, the terminal device 1 configures thesecondary cell for which the deactivation is configured by the MAC CE,as the deactivation.

In a case where the MAC CE indicating the deactivation of the secondarycell is received, or in a case where the deactivation timer associatedwith the secondary cell expires, the terminal device 1 stops thedeactivation timer associated with the secondary cell for which thedeactivation is configured by the MAC CE.

In a case where the MAC CE indicating the deactivation of the secondarycell is received, or in a case where the deactivation timer associatedwith the secondary cell expires, the terminal device 1 flashes all theHARQ buffers associated with the secondary cell for which thedeactivation is configured by the MAC CE.

In a case where the PDCCH in the activated secondary cell indicates thedownlink grant or the uplink grant, or in a case where the PDCCH in theserving cell in which the activated secondary cell is scheduledindicates the downlink grant for the activated secondary cell or theuplink grant for the activated secondary cell, the terminal device 1restarts the deactivation timer associated with the activated secondarycell.

In a case where the secondary cell is deactivated, the terminal device 1does not perform the following operation on the deactivated secondarycell. This operation includes the transmission of the SRS in thesecondary cell, the reporting of the CQI/PMI/RI/PTI for the secondarycell, the transmission of the uplink data (UL-SCH) in the secondarycell, the transmission of the RACH in the secondary cell, the monitoringof the PDCCH in the secondary cell, and the monitoring of the PDCCH forthe secondary cell.

In a case where the deactivation is configured for the secondary cell onwhich the random access procedure is being performed, the terminaldevice 1 stops the random access procedure being performed.

Even in a case where the transmission and reception of data to and fromthe terminal device 1 are not performed, the base station device 3transmits the synchronization signal, the reference signal and thebroadcasting information such as the PSS/SSS, the CRS, the PBCH, and theSIB in order for the terminal device 1 in an idle state to be connectedto the base station device 3. Thus, these signals cause inter-cellinterference. These signals are constantly transmitted, and thus, thepower of the base station device 3 is wasted.

Thus, the base station device 3 performs transmission to an ON state (anoperating state or an activated state) or an OFF state (a deactivatedstate). In a case where the base station device 3 does not transmit andreceive data to and from the terminal device 1, the base station device3 may perform transition to the OFF state. In a case where the basestation device 3 transmits and receives data to and from the terminaldevice 1, the base station device 3 may perform transition to the ONstate.

For example, the deactivated state of the base station device 3 is astate in which at least one of the PSS/SSS, the CRS, the PBCH, the PDCCHand the PDSCH is not transmitted. For example, the deactivated state isa state in which the PSS/SSS is not transmitted over one or more halfframes (5 or more subframes). For example, the deactivated state of thebase station device 3 is a state in which only the DRS is transmitted.The base station device 3 may perform the reception process in thereception unit of the base station device even in the deactivated state.

The activated state of the base station device 3 is a state in which atleast one of at least PSS/SSS and the CRS is transmitted. For example,the activated state is a state in which the PSS/SSS is transmitted inone half frame.

The terminal device 1 may associate the ON state and the OFF state ofthe base station device 3 with a process (assumption or operation) on apredetermined channel or a predetermined signal. Here, the process ismonitoring, a reception process or a transmission process. That is, theterminal device 1 may not recognize that the base station device 3 is inthe ON state or the OFF state, and the terminal device 1 may switch tothe process on the predetermined channel or the predetermined signal. Inthe description of the present embodiment, the transition to theactivated state and the deactivated state in the base station device 3includes the switching of the processes between the predeterminedchannel and the predetermined signal in the terminal device 1. Theactivated state in the base station device 3 corresponds to a firstprocess on the predetermined channel or the predetermined signal in theterminal device 1. The deactivated state in the base station device 3corresponds to a second process on the predetermined channel or thepredetermined signal in the terminal device 1.

For example, the ON state of the base station device 3 is a state inwhich the terminal device 1 can perform the same process as that of theterminal device of the related art. A specific example in the ON stateof the base station device 3 is as follows. The terminal device 1expects to receive the PSS, the SSS and the PBCH. The terminal device 1monitors that the PDCCH and/or the EPDCCH in a predetermined subframe.The terminal device 1 performs the CSI reporting based on the configuredCSI reporting mode. The terminal device 1 expects that there are thereference signal (for example, the CRS or the CSI-RS) and the CSIreference resource for reporting the CSI.

For example, the OFF state of the base station device 3 is a state inwhich the terminal device 1 performs a process different from that ofthe terminal device of the related art. A specific example of the OFFstate of the base station device 3 is as follows. The terminal device 1does not expect to receive the PSS, the SSS and the PBCH. The terminaldevice 1 does not monitor the PDCCH and/or the EPDCCH in all thesubframes. The terminal device 1 does not perform the CSI reportingirrespective of the configured CSI reporting mode. The terminal device 1does not expect that there are the reference signal (for example, theCRS or the CSI-RS) and the CSI reference resource for reporting the CSI.

For example, the transition to the activated state and the deactivatedstate of the base station device 3 is determined based on the connectionstate of the terminal device 1, a data request status of the terminaldevice 1 connected to the base station device 3, and information of theCSI measurement and/or the RRM measurement from the terminal device 1.

The base station device 3 may explicitly or implicitly configure ornotify the terminal device 1 of information (cell state information)related to the transition to the activated state and the deactivatedstate of the base station device 3. For example, the base station device3 notifies explicitly the terminal device 1 of the cell stateinformation by using the RRC, the MAC, the PDCCH and/or the EPDCCH. Thebase station device 3 notifies implicitly the terminal device 1 of thecell state information depending on whether or not there is thepredetermined channel or signal.

An example of a procedure in which the base station device 3 in theactivated state performs transition to the deactivated state (the cellstate information is notified) will be described.

The base station device 3 (serving cell) connected to the terminaldevice 1 determines whether or not to perform the transition to thedeactivated state from the activated state based on the connection stateof the terminal device 1, the data status of the terminal device 1, andthe measurement information of the terminal device 1. The base stationdevice 3 which determines to perform the transition to the deactivatedstate transmits information indicating the transition to the deactivatedstate to the base station device 3 as the surrounding cell, and preparesto stop the cell. The determination of whether or not to perform thetransition to the deactivated state from the activated state and thetransmission the information indicating the transition to thedeactivated state may not be performed in the serving cell, or suchdetermination and transmission may be performed in, for example, theMobility Management Entity (MME) or the Serving Gateway (S-GW). In thepreparing to stop the cell, in a case where the terminal device 1 isconnected to the base station device 3, the transmission of anindication indicating a handover to the surrounding cell or thetransmission of an indication indicating the deactivation of theterminal device to the terminal device 1 are performed. The serving cellin which there is no the connected terminal device 1 through thepreparing to stop the cell performs transition to the deactivated statefrom the activated state.

In a case where the terminal device 1 communicates with the base stationdevice 3 in the deactivated state, the base station device 3 performstransition to the activated state to the deactivated state. A timeduring which the transition to the activated state from the deactivatedstate is performed and a time during which the transition to thedeactivated state from the activated state is performed are referred toas a transition time. The transition time is shortened, and thus, it ispossible to reduce various interferences or power consumption of thebase station device 3.

For example, whether or not to perform the transition of the basestation device 3 in the deactivated state to the activated state isdetermined based on an uplink reference signal from the terminal device1, cell detection information from the terminal device 1, andmeasurement information of the physical layer from the terminal device1.

An example of a procedure in which the transition of the base stationdevice 3 in the deactivated state to the activated state is performedbased on the measurement information of the physical layer will bedescribed.

The base station device 3 (serving cell) to which the terminal device 1is connected and the base station device 3 (neighbour cell) in thedeactivated state share the configuration of the DRS through thebackhaul. The serving cell notifies the terminal device 1 of theconfiguration of the DRS. The neighbour cell transmits the DRS. Theterminal device 1 detects the DRS transmitted from the neighbour cellbased on the configuration of the DRS notified from the serving cell.The terminal device 1 measures the physical layer by using the DRStransmitted from the neighbour cell. The terminal device 1 reports themeasurement of the serving cell. The serving cell determines whether ornot to perform the transition of the base station device 3 in thedeactivated state to the activated state based on the reporting of themeasurement from the terminal device 1, and notifies the base stationdevice 3 in the deactivated state of information indicating theactivation through the backhaul in a case where it is determined thatthe transition to the activated state is performed. The determination ofwhether or not to perform the transition to the activated state from thedeactivated state and the transmission of the information indicating theactivation may not be performed in the serving cell, or suchdetermination and transmission may be performed in, for example, theMobility Management Entity (MME) or the Serving Gateway (S-GW). Theneighbour cell that receives the information indicating the activationperforms the transition to the activated state from the deactivatedstate.

An example of a procedure in which the transition of the base stationdevice 3 in the deactivated state to the activated state is performedbased on the measurement information of the physical layer will bedescribed.

The base station device 3 (serving cell) to which the terminal device isconnected and the base station device 3 (neighbour cell) in thedeactivated state share the configuration of the SRS of the terminaldevice 1 through the backhaul. The serving cell notifies the terminaldevice 1 of the configuration of the SRS. The terminal device 1transmits the SRS based on the configuration of the SRS or theindication of the SRS request. The neighbour cell detects the SRStransmitted from the terminal device 1. The neighbour cell measures thephysical layer by using the SRS transmitted from the terminal device 1.Based on the measurement result through the SRS, the neighbour celldetermines whether or not to perform the transition of the base stationdevice 3 to the activated state, and performs the transition to theactivated state from the deactivated state. The determination of whetheror not to perform the transition to the activated state from thedeactivated state may not be performed in the neighbour cell, or suchdetermination and transmission may be performed in, for example, theserving cell, the Mobility Management Entity (MME), or the ServingGateway (S-GW). In this case, after the measurement of the physicallayer is performed using the SRS, the neighbour cell transmits themeasurement result to the serving cell, the MME or the S-GW, andreceives the information indicating the activation.

The serving cell may notify the terminal device 1 of the informationindicating the activated/deactivated state of the surrounding cell. Theterminal device 1 switches the action of the terminal device 1 byrecognizing the activated state or the deactivated state of the cell.The action of the terminal device 1 is, for example, an interferencemeasurement method.

An example of a method of notifying of the cell state information(information indicating the activated/deactivated state of the cell)will be described.

The information indicating the activated/deactivated state of a targetcell is notified through Layer 1 signalling (L1 signalling). In otherwords, the information indicating the activated/deactivated state of thetarget cell is notified through the PDCCH or the EPDCCH. Onecorresponding bit is assigned to the target cell. 0 (false or disable)indicates the deactivated state, and 1 (true or enable) indicates theactivated state. The bit corresponding to the target cell is included ina bitmap to be collected, and may simultaneously notify the plurality ofcells of the activated/deactivated state. The association of the bitwith the target cell is notified through the dedicated RRC signaling.

The information indicating the activated/deactivated state is notifiedthrough the downlink control information (DCI) format 1C. Theinformation indicating the activated/deactivated state may be notifiedthrough the DCI format 3/3A. The information indicating theactivated/deactivated state may be notified through a format having thesame payload size (bit number) as that of the DCI format 1C.

Hereinafter, the DCI format will be described.

As the DCI format, there are a DCI format associated with the uplinkscheduling and a DCI format associated with the downlink scheduling. TheDCI format associated with the uplink scheduling is referred to as anuplink grant, and the DCI format associated with the downlink schedulingis referred to as a downlink grant (downlink assignment). One DCI formatmay be transmitted to the plurality of terminal devices 1. For example,in a case where only a transmission power control command (TPC command)is transmitted, the command may be transmitted to the plurality ofterminal devices 1 at once. Such scheduling (or triggering) is referredto as group scheduling (group triggering). The terminal device 1 isindividually assigned an index, and detects a bit based on the index.

The DCI format 0 is used to schedule the PUSCH in one uplink cell.

The DCI format 1 is used to schedule one PDSCH code word in one cell.

The DCI format 1A is used in the random access process started by aPDCCH order and compact scheduling of one PDSCH code word in one cell.The DCI equivalent to the PDCCH order may be transmitted through thePDCCH or the EPDCCH. The DCI format 0 and the DCI format 1A may betransmitted using the same bit information field, and the terminaldevice 1 determines whether the DCI format mapped to the received bitinformation field is the DCI format 0 or the DCI format 1A based on avalue represented in a certain bit field.

The DCI format 1B is used in the compact scheduling of one PDSCH codeword in one cell accompanying by the precoding information.

The DCI format 1C is used to notify of the change (alternation) of themulticast control channel (MCCH) and to perform the compact schedulingof one PDSCH code word. The DCI format 1C may be used to notify of arandom access response by being scheduled using the random access-radionetwork temporary identifier (RA-RNTI). Here, for example, the compactscheduling means that the PDSCH having a narrow bandwidth is scheduled.A DCI format size is determined depending on a bandwidth used by thePDSCH in which the scheduling is performed. As the bandwidth is narrow,a required DCI format size may also be decreased. The DCI format 1C isscheduled using the RNTI (for example, eIMTA-RNTI) related to dynamicTDD (a first type (mode) of TDD), and thus, information indicating TDDUL-DL may be set to the DCI format 1C. If the dynamic TDD is the firsttype (mode) of TDD, the TDD of the related art is referred to as asecond type (mode) of TDD.

The dynamic TDD is TDD of switching the TDD UL-DL configuration by usingthe L1 signalling depending on a communication status of theuplink/downlink. The dynamic TDD is used to extend interferencemanagement and traffic adaptation control. The dynamic TDD is referredto as enhanced interference management and traffic adaptation (eIMTA) orTDD-ModeA in some cases.

The DCI format 1D is used in the compact scheduling of one PDSCH codeword in one cell accompanying by information related to power offset andprecoding.

The DCI format 2/2A/2B/2C/2D is used to schedule two (or a plurality of)PDSCH code words as well as one PDSCH code word.

The DCI format 3/3A indicates a value of the transmission power controlcommand for adjusting the transmission power of the PUSCH or the PUCCHfor the plurality of terminal devices 1. The terminal device 1 maydetect the value of the transmission power control command correspondingto the PUSCH or the PUCCH by detecting bit information corresponding tothe index (TPC-index) assigned to the terminal device. It is determinedwhether the DCI format 3/3A indicates the transmission power controlcommand corresponding to the PUSCH or the transmission power controlcommand corresponding to the PUCCH depending on the type of thescrambled RNTI.

The DCI format 4 is used to schedule the PUSCH in one uplink cellaccompanying by a multi-antenna-port transmission mode.

A cyclic redundancy check (CRC) is used to detect a DCI transmissionerror. The CRC is scrambled with each RNTI.

A CRC parity bit is scrambled with a cell-radio network temporaryidentifier (C-RNTI), a semi persistent scheduling cell-radio networktemporary identifier (SPS C-RNTI), a system information-radio networktemporary identifier (SI-RNTI), a paging-radio network temporaryidentifier (P-RNTI), a random access-radio network temporary identifier(RA-RNTI), a transmission power control-physical uplink controlchannel-radio network temporary identifier (TPC-PUCCH-RNTI), atransmission power control-physical uplink shared channel-radio networktemporary identifier (TPC-PUSCH-RNTI), a temporary C-RNTI, a multimediabroadcast multicast services (MBMS)-radio network temporary identifier(M-RNTI), or a TDD-ModeA-RNTI.

The C-RNTI and the SPS C-RNTI are identifiers for identifying theterminal devices 1 within the cell. The C-RNTI is used to control thePDSCH or the PUSCH in a single subframe.

The SPS C-RNTI is used to periodically assign the PDSCH or PUSCHresource. The control channel having the CRC scrambled with the SI-RNTIis used to control a system information block (SIB).

The control channel having the CRC scrambled with the P-RNTI is used tocontrol paging.

The control channel having the CRC scrambled with the RA-RNTI is used tocontrol a response to the RACH.

The control channel having the CRC scrambled with the TPC-PUCCH-RNTI isused to control the power of the PUCCH. The control channel having theCRC scrambled with the TPC-PUSCH-RNTI is used to control the power ofthe PUSCH.

The control channel having the CRC scrambled with the temporary C-RNTIis used for the terminal device that is not identified by the C-RNTI.

The control channel having the CRC scrambled with the M-RNTI is used tocontrol MBMS.

The control channel having the CRC scrambled with the TDD-ModeA-RNTI isused to notify the terminal device 1 of the information of the TDD UL/DLconfiguration of each TDD serving cell in the dynamic TDD.

The DCI format may be scrambled using a new RNTI in addition to theabove-described RNTI.

Hereinafter, the details of the PDCCH or the EPDCCH will be described.

A control region of each serving cell includes a set of CCEs. The CCEsare assigned numbers from 0 to N_(CCE, k)−1. Here, the N_(CCE, k) is thetotal number of CCEs within the control region of the subframe k.

The terminal device 1 monitors a set of PDCCH candidates of one or aplurality of activated serving cells configured through the higher layersignalling for the control information. Here, the monitoring means thatdecoding is tried to be performed on the respective PDCCHs within theset corresponding to all the monitored DCI formats.

The set of monitored PDCCH candidates is referred to as a search space.As the search space, a common search space (CSS) and a UE-specificsearch space (USS) are defined.

The common search space (CSS) is a search space configured using aparameter specific to the base station device 3 (cell or transmissionpoint) and/or a predefined parameter. For example, the CSS is a searchspace capable of being commonly used in the plurality of terminaldevices. Thus, the base station device 3 can reduce the resources fortransmitting the control channel by mapping the common control channelto the CSS in the plurality of terminal devices.

The UE-specific search space (USS) is a search space configured using aparameter specific to at least the terminal device 1. Thus, since thecontrol channel specific to the terminal device 1 can be individuallytransmitted in the USS, the base station device 3 can efficientlycontrol the terminal device 1.

The CSS may be configured for the terminal device 1 by further using theunique parameter. In this case, it is preferable that the parameterspecific to the terminal device 1 is configured such that the values areequal between the plurality of terminal devices. Even in a case wherethe CSS is configured by further using the parameter specific to theterminal device 1, the CSS is common to the plurality of terminaldevices for which the same parameter is configured. For example, a unitfor which the same parameter is configured between the plurality ofterminal devices is the cell, the transmission point or the UE group.Since the plurality of terminal devices for which the same parameter isconfigured can receive the common control channel mapped to the CSS, itis possible to reduce the resources for transmitting the controlchannel. Such a search space may be referred to as the USS instead ofthe CSS. That is, the USS which is the search space common to theplurality of terminal devices may be configured. The USS specific to oneterminal device is referred to as a first USS, and the USS common to theplurality of terminal devices is referred to as a second USS.

A search space S^((L)) _(k) for each aggregation level is defined by aset of PDCCH candidates. The number of CCEs used by one PDCCH is alsoreferred to as an aggregation level. The number of CCEs used by onePDCCH is 1, 2, 4 or 8. In each serving cell in which the PDCCH ismonitored, the CCEs corresponding to the PDCCH candidates of the searchspace S^((L)) _(k) is represented by Expression (1) of FIG. 14. Here,Y_(k) represents a value in the subframe k. In the CSS, m′=m. In the USSof the PDCCH, in a case where the CIF is configured for the terminaldevice 1 to be monitored in the serving cell in which the PDCCH ismonitored, m′=m+M^((L)). n_(CI), and otherwise, m′=m. Here, m is a valuefrom 0 to M^((L))−1, and M^((L)) is the number of PDCCH candidates to bemonitored in a predetermined search space.

In the CSS, Y_(k) is a predefined value, or a value determined based onthe parameter specific to the base station device 3. For example, 0 isconfigured for Y_(k) in a case where an aggregation level L=4 and L=8.In the UE-specific search space S^((L))k of the aggregation level L,Y_(k) is a value specific to the terminal device 1, and is given by, forexample, Y_(k)=(A·Y_(k-1))mod D. Here, as an initial value Y⁻¹ of theY_(k), a value of the RNTI (for example, C-RNTI) is used.

The aggregation level is defined for each search space. For example, inthe CSS, the aggregation levels 4 and 8 are defined. For example, in theUSS, the aggregation levels 1, 2, 4 and 8 are defined.

The number of PDCCH candidates is defined by each aggregation level ofeach search space. For example, in the CSS, the number of PDCCHcandidates is 4 for the aggregation level 4, and the number of PDCCHcandidates is 2 for the aggregation level 8. For example, in the USS,the number of PDCCH candidates is 6 for the aggregation 1, the number ofPDCCH candidates is 6 for the aggregation level 2, the number of PDCCHcandidates is 2 for the aggregation level 4, and the number of PDCCHcandidates is 2 for the aggregation level 8.

The EPDCCH is transmitted using an aggregation of one or more enhancedcontrol channel elements (ECCEs). Each ECCE includes a plurality ofenhanced resource element groups (EREGs). The EREG is used to define themapping of the EPDCCH to the resource element. In each RB pair, 16 EREGsnumbered from 0 to 15 are defined. That is, in each RB pair, EREG 0 toEREG 15 are defined. In each RB pair, the EREG 0 to EREG 15 areperiodically defined for the resource elements other than the resourceelements to which the predetermined signal and/or channel are mapped byprioritizing a frequency direction. For example, the resource elementsto which demodulation reference signals associated with the EPDCCHtransmitted through antenna ports 107 to 110 are mapped do not definethe EREG.

The number of ECCEs used by one EPDCCH depends on the EPDCCH format andis determined based on another parameter. The number of ECCEs used byone EPDCCH is also referred to as an aggregation level. For example, thenumber of ECCEs used by one EPDCCH is determined by the number ofresource elements capable of being used to transmit the EPDCCH in one RBpair, or the transmission method of the EPDCCH. For example, the numberof ECCEs used by one EPDCCH is 1, 2, 4, 8, 16, or 32. The number ofEREGs used by one ECCE is determined based on the type of subframe andthe type of cyclic prefix, and is 4 or 8. As the transmission method ofthe EPDCCH, distributed transmission and localized transmission aresupported.

The EPDCCH may be transmitted using the distributed transmission or thelocalized transmission. The mapping of the ECCE to the EREG and the RBpair is different between the distributed transmission or the localizedtransmission. For example, in the distributed transmission, one ECCEincludes EREGs of a plurality of RB pairs. In the localizedtransmission, one ECCE includes an EREG of one RB pair.

The base station device 3 performs the configuration related to theEPDCCH for the terminal device 1. The terminal device 1 monitors theplurality of EPDCCHs based on the configuration from the base stationdevice 3. The set of RB pairs in which the terminal device 1 monitorsthe EPDCCH may be configured. The set of RB pairs is also referred to asan EPDCCH set or an EPDCCH-PRB set. One or more EPDCCH sets may beconfigured for one terminal device 1. Each EPDCCH set includes one ormore RB pairs. The configuration related to the EPDCCH may beindividually performed for each EPDCCH set.

The base station device 3 may configure a predetermined number of EPDCCHsets for the terminal device 1. For example, the first and second EPDCCHsets may be configured as the EPDCCH set 0 and/or the EPDCCH set 1. EachEPDCCH set may include a predetermined number of RB pairs. Each EPDCCHset includes one set of the plurality of ECCEs. The number of ECCEsconstituting one EPDCCH set is determined by the number of RB pairsconfigured as the EPDCCH set and the number of EREGs used by one ECCE.In a case where the number of ECCEs constituting one EPDCCH set is N,each EPDCCH set includes ECCEs numbered from 0 to N−1. For example, in acase where the number of EREGs used by one ECCE is 4, the EPDCCH setconstituted by 4 RB pairs includes 16 ECCEs.

The EPDCCH candidates monitored by the terminal device 1 are definedbased on the ECCE constituting the EPDCCH set. The set of EPDCCHcandidates is defined as a search space (search region). The UE-specificsearch space which is the search space specific to the terminal device 1and the common search space which is the search space specific to thebase station device 3 (cell, transmission point, or UE group) aredefined. The monitoring of the EPDCCH includes a case where the terminaldevice 1 tries to decode each of the EPDCCH candidates within the searchspace according to the DCI format to be monitored.

A UE-specific search space ES^((L)) _(k) of the EPDCCH in theaggregation level L ε {1, 2, 4, 8, 16, 32} is defined by the set of theEPDCCH candidates.

In the EPDCCH set, the ECCE corresponding to the EPDCCH candidate m ofthe search space ES^((L)) _(k) is given by Expression (2) of FIG. 14.

Here, Y_(p, k) represents a value in an EPDCCH set p and the subframe k.The Y_(p, k) may be independently configured by the search space. In thecase of the common search space, the Y_(p, k) is a value specific to thebase station device 3 (cell). For example, in the case of the commonsearch space, the Y_(p, k) is a predefined value or a value determinedbased on the parameter specific to the base station device 3. In thecase of the UE-specific search space, the Y_(p, k) is a value specificto the terminal device 1, and is given by Y_(p, k)=(A·Y_(p, k−1))mod D.For example, the Y_(p, k) is determined based on the predeterminedvalue, the subframe k and the RNTI (for example, C-RNTI) of the terminaldevice 1. A plurality of common search spaces and/or a plurality ofUE-specific search spaces may be configured for one EPDCCH set.

Here, in a case where the CIF corresponding to the serving cell in whichthe EPDCCH is monitored is configured for the terminal device 1, bsatisfies b=n_(CI), and otherwise, b=0.

The DCI format monitored by the terminal device 1 depends on atransmission mode configured for each serving cell. In other words, theDCI format monitored by the terminal device 1 is different depending onthe transmission mode. For example, the terminal device 1 for whichDownlink Transmission Mode 1 is configured monitors the DCI format 1Aand the DCI format 1. For example, the terminal device 1 for whichDownlink Transmission Mode 4 is configured monitors the DCI format 1Aand the DCI format 2. For example, the terminal device 1 for whichDownlink Transmission Mode 10 is configured monitors the DCI format 1Aand the DCI format 2D. For example, the terminal device 1 for whichUplink Transmission Mode 1 is configured monitors the DCI format 0. Forexample, the terminal device 1 for which Uplink Transmission Mode 2 isconfigured monitors the DCI format 0 and the DCI format 4.

A control region to which the PDCCHs for the terminal device 1 areallocated is not notified, and the terminal device 1 tries to decode allthe DCI formats corresponding to all the PDCCH candidates and thetransmission modes for all the aggregation levels defined in each searchspace. In other words, the terminal device 1 tries to decode all theaggregation levels, the PDCCH candidates and the DCI formats that arelikely to be transmitted to the terminal device 1. The terminal device 1recognizes the PDCCH on which the decoding succeeds as the controlinformation addressed to the terminal device 1. Such decoding isreferred to as blind decoding.

Even though the DCI formats are different, if the different DCI formatshave the same bit size, the number of times the decoding is performed isnot increased. For example, since the DCI format 0 and the DCI format 1Ahave the same bit size, two types of DCI formats can be decoded byperforming the decoding once.

For example, in the CSS, the terminal device 1 for which UplinkTransmission Mode 1 is configured tries to decode the DCI formats havingtwo types of bit sizes and 6 PDCCH candidates in the aggregation 4, andtries to decode two PDCCH candidates and the DCI formats having twotypes of bit sizes in the aggregation 8. In the USS, the terminal device1 tries to decode 6 PDCCH candidates and the DCI formats having twotypes of bit sizes in the aggregation 1, tries to decode 6 PDCCHcandidates and the DCI formats having two types of bit sizes in theaggregation 2, tries to decode 2 PDCCH candidates and the DCI formatshaving two types of bit sizes in the aggregation 4, and tries to decode2 PDCCH candidates and the DCI formats having two types of bit sizes inthe aggregation 8. That is, the terminal device 1 tries to decode thePDCCH in one subframe forty-four times.

For example, in the CSS, the terminal device 1 for which UplinkTransmission Mode 2 is configured tries to decode 6 PDCCH candidates andthe DCI format having two types of bit sizes in the aggregation 4, andtries to decode 2 PDCCH candidates and the DCI format having two typesof bit sizes in the aggregation 8. In the USS, the terminal device 1tries to decode 6 PDCCH candidates and the DCI format having three typesof bit sizes in the aggregation 1, tries to decode 6 PDCCH candidatesand the DCI format having three types of bit sizes in the aggregation 2,tries to decode 2 PDCCH candidates and the DCI format having three typesof bit sizes in the aggregation 4, and tries to decode 2 PDCCHcandidates and the DCI format having three types of bit sizes in theaggregation 8. That is, the terminal device 1 tries to decode the PDCCHin one subframe 60 times.

Through the blind decoding, the terminal device 1 can decode the PDCCHsof which the coding rates are different without using preliminaryinformation, and it is possible to efficiently transmit the controlinformation between the base station device 3 and the terminal device 1.

The information indicating the activated/deactivated state is notifiedby the common search space. The common search space is the common searchspace in the cell. The information indicating the activated/deactivatedstate is notified by a UE-specific common search space. Here, theUE-specific common search space is a search space where starting pointsof the CCEs to which the PDCCH candidates are allocated using the RNTI(UE-group C-RNTI, TPspecific-RNTI or SCE-RNTI) commonly assigned to theterminal group are determined. The plurality of terminal devices 1 forwhich the UE-group RNTI is configured detects the DCI format by usingthe PDCCHs allocated to the same search space.

The notification of the information indicating the activated/deactivatedstate is performed at a predefined timing or a configured timing. Forexample, this notification timing is one radio frame unit.

The notification of the information indicating the activated/deactivatedstate indicates information of the next radio frame in which the L1signalling is received. In a case where the L1 signalling is received inan initial subframe (subframe 0) within the radio frame, thenotification may indicate information of the received radio frame.

An example of a method of notifying of the information indicating theactivated/deactivated state of the cell will be described.

The activated/deactivated state of the target cell may be implicitlyrepresented by changing (altering) the structure of the DRS. Theinformation indicating the activated/deactivated state of the targetcell may be implicitly represented by allowing the DRSs to havedifferent structures between the activated state and the deactivatedstate. The DRS may be transmitted from the target cell such that the DRShas different structures between the activated state and the deactivatedstate. The terminal device 1 may receive information related to thestructure of the DRS transmitted in the activated state and informationrelated to the structure of the DRS transmitted in the deactivated statefrom the base station device 3.

The activated/deactivated state of the target cell may be represented bychanging (altering) the parameter (or the value of the parameter) of acertain structure of the DRS. In other words, a certain parameterincluded in the configuration of the DRS may be different between theactivated state and the deactivated state (or may be individuallyconfigured). For example, the arrangement of the resource elements maybe different between the DRS transmitted in the activated state and theDRS transmitted in the deactivated state. An antenna port may bedifferent between the DRS transmitted in the activated state and the DRStransmitted in the deactivated state. A scramble sequence may bedifferent between the DRS transmitted in the activated state and the DRStransmitted in the deactivated state. An initial value of the scramblesequence or a method (expression) for generating the initial value maybe different between the DRS transmitted in the activated state and theDRS transmitted in the deactivated state. A transmission power may bedifferent between the DRS transmitted in the activated state and the DRStransmitted in the deactivated state. A subframe interval at which theDRS is transmitted may be different between the DRS transmitted in theactivated state and the DRS transmitted in the deactivated state. Atransmission bandwidth or the number of resource blocks may be differentbetween the DRS transmitted in the activated state and the DRStransmitted in the deactivated state. That is, the information relatedto the configuration of the DRS transmitted in the activated state andthe information related to the configuration of the DRS transmitted inthe deactivated state may be individually set. These information itemsmay be transmitted to the terminal device 1 from the base station device3 by using the higher layer signalling. That is, the informationindicating the activated/deactivated state of the target cell may beconfiguration information of the parameter related to the structure ofthe DRS. In other words, certain parameters are respectively configuredin the activated state and the deactivated state.

The terminal device 1 may monitor two structures, that is, the structureof the DRS indicating the activated state and the structure of the DRSindicating the deactivated state. The terminal device 1 may monitor twostructures by using a monitoring pattern of the structure of the DRSindicating the activated state and a monitoring pattern of the structureof the DRS indicating the deactivated state. In this case, informationrelated to two monitoring patterns of the structures of the DRS isnotified to the terminal device 1. That is, in a case where informationrelated to one monitoring pattern of the structure of the DRS is notnotified, the terminal device may monitor the DRSs having two structuresbased on one monitoring pattern.

In a case where the DRS in the activated state is measured in themeasurement subframe of the DRS in the deactivated state, the terminaldevice 1 recognizes that the small cell in the deactivated state is theactivated state.

The terminal device 1 may implicitly acquire the information of theactivated/deactivated state of the target cell by the monitoring patternin which the DRS is detected. The monitoring pattern of the structure ofthe DRS indicating the activated state and the monitoring pattern of thestructure of the DRS indicating the deactivated state may be previouslydefined. The monitoring pattern of the structure of the DRS indicatingthe activated state and the monitoring pattern of the structure of theDRS indicating the deactivated state may be notified through thededicated RRC signaling (higher layer signalling) from the base stationdevice 3.

Another example of the method of notifying of the information indicatingthe activated/deactivated state of the cell will be described.

The state of the activated/deactivated state of the target cell may beimplicitly represented by allowing the CRS to have different structures(configurations of the CRS) between the activated state and thedeactivated state of the target cell. In this case, the CRS transmittedfrom the target cell is transmitted such that the CRS has differentstructures between the activated state and the deactivated state. Inthis case, configuration information of the CRSs having differentstructures is notified to the terminal device 1.

The activated/deactivated state of the target cell may be represented bychanging a certain parameter (or a value of the parameter) related tothe structure of the CRS. For example, the arrangement of the resourceelements may be different between the CRS transmitted in the activatedstate and the CRS transmitted in the deactivated state. An antenna portmay be different between the CRS transmitted in the activated state andthe CRS transmitted in the deactivated state. A scramble sequence may bedifferent between the CRS transmitted in the activated state and the CRStransmitted in the deactivated state. An initial value of the scramblesequence may be different between the CRS transmitted in the activatedstate and the CRS transmitted in the deactivated state. A transmissionpower may be different between the CRS transmitted in the activatedstate and the CRS transmitted in the deactivated state. A subframeinterval at which the CRS is transmitted may be different between theCRS transmitted in the activated state and the CRS transmitted in thedeactivated state. A transmission bandwidth or the number of resourceblocks may be different between the CRS transmitted in the activatedstate and the CRS transmitted in the deactivated state. That is, theinformation indicating the activated/deactivated state of the targetcell may be configuration information of the parameter related to thestructure of the CRS. In this case, certain parameters are individuallyconfigured between the activated state and the deactivated state. Here,the CRS has been described, but the same is true of the PSS/SSS, theCSI-RS, and the PRS.

The terminal device 1 monitors two structures, that is, the structure ofthe CRS indicating the activated state and the structure of the CRSindicating the deactivated state. The terminal device 1 monitors twostructures by using a monitoring pattern of the structure of the CRSindicating the activated state and a monitoring pattern of the structureof the CRS indicating the deactivated state. The terminal device 1implicitly acquires the information of the activated/deactivated stateof the target cell by the monitoring pattern in which the CRS isdetected. The monitoring pattern of the structure of the CRS indicatingthe deactivated state may be previously defined. The monitoring patternof the structure of the CRS indicating the deactivated state may benotified from the base station device 3 through the dedicated RRCsignaling.

Another example of the method of notifying of the information indicatingthe activated/deactivated state of the cell will be described.

The information indicating the activated/deactivated state of the cellmay be notified through the dedicated RRC signaling. The informationindicating the activated/deactivated state of the cell may be listed inassociation with a center frequency (carrier frequency) and a cell ID,and may be notified.

The terminal device 1 can recognize the activated/deactivated state ofthe target cell by the above-described notification method. Hereinafter,any one of the above-described methods is applied when the terminaldevice 1 switches an action by the activated/deactivated state of thetarget cell.

Hereinafter, the detection of the cell (base station device 3) will bedescribed.

The detection of the cell means that the terminal device 1 detects thesynchronization signal (PSS or SSS) transmitted from the base stationdevice 3 constituting the cell or/and the reference signal (CRS orCSI-RS). The synchronization signal or/and the reference signal used todetect the cell includes information of the cell ID. The terminal device1 detects the cell by the cell ID of the cell and a detection criterionof the synchronization signal or/and the reference signal.

The detection of the cell may include the detection of the base stationdevice 3. The detection of the primary cell may include the detection ofthe master base station device. The detection of the primary secondarycell may include the detection of the secondary base station device.

An example of the detection criterion of the synchronization signalor/and the reference signal will be described.

The terminal device 1 determines the detection based on reception powerstrength or/and reception power quality of the synchronization signalor/and the reference signal from the cell. The terminal device 1compares the reception power strength or/and the reception power qualityof the synchronization signal or/and the reference signal with athreshold, and determines that the cell is detected in a case where thereception strength or/and the reception quality is greater than thethreshold. The reception power strength is, for example, RSRP. Thereception quality is, for example, interference amount, RSRQ, or SINR.The detection of the cell may be determined by a measurement event to bedescribed below.

An example of the detection criterion of the synchronization signalor/and the reference signal will be described.

The terminal device 1 determines the detection based on whether or notthe decoding of the information of the synchronization signal or/and thereference signal from the cell succeeds. For example, the cell (the basestation device 3 constituting the cell) transmits the synchronizationsignal or/and the reference signal by adding a parity code such as CRCto the synchronization signal or/and the reference signal. The terminaldevice 1 performs the decoding by using the parity code included in thesynchronization signal or/and the reference signal, and determines thatthe cell is detected in a case where it is determined that the decodingcorrectly succeeds through parity check.

After the cell is detected in the terminal device 1, the terminal device1 selects the cell to be connected/activated and selects the cell to bedisconnected/deactivated.

After the cell is detected in the terminal device 1, the terminal device1 reports information of the detected cell to the connected base stationdevice 3. The information of the detected cell includes the cell ID andthe measurement information.

Hereinafter, the CRSs for describing the details of the CRS aretransmitted through the antenna ports 0 to 3. The CRSs are allocated toall the downlink subframes which are non-MBSFN subframes. In otherwords, the CRSs are allocated to all the downlink subframes except forthe MBSFN subframes. The resource element and the signal sequence of theCRS are determined based on the physical cell identity (PCI).

FIG. 10 is a diagram showing an example of the structure of the CRS. Thesignal of the CRS is generated using a pseudo-random sequence. Thepseudo-random sequence is, for example, a Gold sequence. Thepseudo-random sequence is calculated based on the physical cell identity(PCI). The pseudo-random sequence is calculated based on the type of theCP. The pseudo-random sequence is calculated based on the slot numberand the OFDM symbol number within the slot. The resource element of theCRS in the case of the normal CP uses R0 to R3 of FIG. 10. R0corresponds to the arrangement of CRSs at the antenna port 0, R1corresponds to the arrangement of CRSs at the antenna port 1, R2corresponds to the arrangement of CRSs at the antenna port 2, and R3corresponds to the arrangement of CRSs at the antenna port 3. Theresource elements of the CRSs transmitted through one antenna port areallocated to the frequency axis at a cycle of 6 subcarriers. Theresource elements of the CRSs transmitted through the antenna port 0 andthe CRSs transmitted through the antenna port 1 are allocated atintervals of 3 subcarriers. The CRS is shifted on the frequency so as tobe specific to the cell based on the cell ID. The resource elements ofthe CRSs transmitted through the antenna port 0 and the CRSs transmittedthrough the antenna ports 1 are allocated to the OFDM symbols 0 and 4 inthe case of the normal CP, and are allocated to the OFDM symbols 0 and 3in the case of the enhanced CP. The resource elements of the CRSstransmitted through the antenna port 2 and the CRSs transmitted throughthe antenna port 3 are allocated to the OFDM symbols 1. The CRSs aretransmitted in a broadband with a bandwidth configured for the downlink.The DRS may have the same structure as that of the CRS.

Hereinafter, the details of the discovery reference signal (DRS) will bedescribed. The DRS is transmitted from the base station device 3 forvarious purposes such as synchronization (time synchronization) in thetime domain of the downlink, synchronization (frequency synchronization)of the frequency of the downlink, cell/transmission pointidentification, RSRP measurement, RSRQ measurement, the measurement (UEpositioning) of the geographic position of the terminal device 1, andCSI measurement. The DRS may be used as the reference signal used tosupport the ON state and the OFF state of the base station device 3. TheDRS may be used as the reference signal used by the terminal device 1 todetect the base station device 3 in the ON state and/or the OFF state.

The DRS includes a plurality of signals. As an example, the DRS includesthe PSS, the SSS and the CRS. The PSS and the SSS included in the DRSmay be used for the time synchronization, the frequency synchronization,the cell identification and the transmission point identification. TheCRS included in the DRS may be used to perform the RSRP measurement, theRSRQ measurement and the CSI measurement. As another example, the DRSincludes the PSS, the SSS and the CSI-RS. The PSS and the SSS includedin the DRS may be used for the time synchronization, the frequencysynchronization, the cell identification and the transmission pointidentification. The CSI-RS included in the DRS may be used for thetransmission point identification, the RSRP measurement, the RSRQmeasurement and the CSI measurement. The DRS including the plurality ofsignals may be referred to a discovery burst. The reference signal usedto perform the RSRP measurement and/or the RSRQ measurement may bereferred to as the DRS.

The base station device 3 may transmit a first DRS including the PSS,the SSS and the CRS, and a second DRS including the PSS, the SSS and theCSI-RS by switching between the first and second DRSs. In this case, thebase station device 3 configures the first DRS or the second DRS for theterminal device 1.

The DRS is transmitted in the downlink subframe. The DRS is transmittedby the downlink component carrier.

The DRS is transmitted in the deactivated state (off state, dormantmode, or deactivation) of the base station device 3. The DRS may betransmitted even in the activated state (on state, active mode, oractivation) of the base station device 3.

The DRS may be independently configured in each base station device(cell or transmission point). For example, in the plurality of smallcells, the DRSs having different configurations from each other aretransmitted using different resources from each other.

The base station device 3 configures a list related to the DRS and ameasurement (detection, monitoring, or transmission) timing of the DRSfor the terminal device 1. The list related to the DRS is a list ofinformation associated with the base station device that transmits theDRS which is likely to be received by the terminal device 1. Forexample, the list related to the DRS is a list of transmission points IDof the transmission points that transmit the DRSs. The plurality oftransmission points transmits the DRSs specific to the respectivetransmission points based on the measurement timing of the DRSconfigured for the terminal device 1. The terminal device 1 measures theDRS measurement based on the list related to the DRS configured for thebase station device 3 and the measurement timing of the DRS. Forexample, the terminal device 1 measures the DRS determined based on thelist related to the DRS in the subframe or the resource determined basedon the measurement timing of the DRS. The terminal device 1 reports themeasurement result through the measurement of the DRS to the basestation device 3.

The respective transmission points transmit the DRSs in one subframe.That is, the respective transmission points transmit the PSS, the SSS,the CRS and/or the CSI-RS associated with one DRS in one subframe. Theterminal device 1 expects to transmit the DRS corresponding to onetransmission point in one subframe. One DRS may be transmitted in theplurality of subframes.

The transmission of the DRS or the measurement timing of the DRS isperiodically configured on the time axis. The transmission of the DRS orthe measurement timing of the DRS may be configured in successivesubframes. In other words, the DRS may be transmitted through bursttransmission. For example, the transmission of the DRS or themeasurement timing of the DRS is configured in N successive subframes ata cycle of M subframes. The subframe L to which the DRSs are allocatedwithin the cycle may be configured. The value of the M, N and/or L isconfigured in the higher layer. The number of subframes N successivelytransmitted within the cycle may be previously defined. If the subframecycle M is configured as a long period, the number of times the DRS istransmitted from the base station device 3 in the deactivated state canbe reduced, and thus, the inter-cell interference can be reduced. Adifferent configuration may be applied to the value of the M, N and/or Lbetween the deactivated state and the activated state. The parametercorresponding to the value of the M, N and/or L may be notified by thehigher layer signalling.

The parameter corresponding to M may represent a subframe offset (or astarting subframe) in addition to the cycle. That is, the parametercorresponding to M may be an index correlated with the cycle and/or thesubframe offset.

The parameter corresponding to N may be managed as a table. A value ofthe parameter corresponding to N may not directly represent the numberof subframes. The parameter corresponding to N may be represented byincluding the starting subframe in addition to the number of subframes.

The parameter corresponding to L may be managed as a table. Theparameter corresponding to L may be correlated with the cycle. A valueof the parameter corresponding to L may not directly represent theoffset of the subframe.

In the subframe in which it is likely to transmit the DRS or ameasurement subframe of the DRS, the terminal device 1 may monitor thePDCCH in addition to the measurement of the DRS. For example, theterminal device 1 may monitor the PDCCH in the parameter correspondingto the N. In this case, there is a condition in which the terminaldevice 1 supports a function of monitoring the PDCCH for the small cellin the deactivated state.

The DRS may be transmitted by including the information of thetransmission point ID. Here, the information of the transmission pointID is information for identifying the transmission point (cell) whichtransmits the DRS. For example, the transmission point ID is a physicalcell identity (physical cell ID, physCellID, or physical layer cell ID),a Cell Global Identity (CGI), a new cell identity (small cell ID), adiscovery ID, or an extended cell ID. The transmission point ID may bean ID different from the physical cell identity identified by the PSSand the SSS included in the DRS. The transmission point ID may be an IDassociated with the physical cell identity identified by the PSS and theSSS included in the DRS. For example, a certain transmission point IDmay be associated with any one of the physical cell identitiesidentified by the PSS and the SSS included in the DRS. A plurality ofIDs related to the cell may be transmitted by the DRS. For example, inan environment in which cells of an insufficient number are arrangedwith the physical cell identity, the combination of the physical cellidentity and the new cell identity is transmitted by the DRS, and thus,the physical cell identity may be practically extended.

The DRS is transmitted through antenna ports p, . . . , and p+n−1. Here,n represents the total number of antenna ports through which the DRS istransmitted. As the values of p, . . . , and p+n−1, values other than 0to 22, and 107 to 110 may be applied. That is, the DRS may betransmitted using antenna ports different from the antenna ports usedfor other reference signals.

Hereinafter, an example of the structure (or configuration) of the DRSwill be described.

A plurality of structures and/or configurations may be applied to theDRS. Here, the plurality of structures may be structures orconfigurations of a plurality of signals. The plurality of structuresmay be signals having the plurality of structures. In other words, theDRS may include a plurality of signals. For example, the same structure(or configuration) as that of the PSS may be applied to the DRS. Thesame structure (or configuration) as that of the SSS may be applied tothe DRS. The same structure (or configuration) as that of the CRS may beapplied to the DRS. The same structure (or configuration) as that of theCSI-RS may be applied to the DRS. That is, the DRS may be based on thestructures (or configurations) of a first signal to an n-th signal (n isa natural number). In other words, the DRS may be based on a signalhaving a first structure to a signal having an n-th structure. Thestructure of the signal may include a radio resource arrangement(resource configuration) and a subframe configuration.

The DRS may use the signals (radio resources) having the respectivestructures according to the any purposes. For example, thesynchronization in the time domain and/or the frequency domain, the cellidentification and the RSRP/RSRQ/RSSI measurement (RRM measurement) maybe performed by using signals having the different structures. That is,the terminal device 1 may perform the synchronization in the time domainand/or the frequency domain by using a first signal, may perform thecell identification by using a second signal, and may perform theRSRP/RSRQ measurement by using a third signal. The terminal device mayperform the synchronization in the time domain or the frequency domainand the cell identification by using the first signal and the secondsignal, and may perform the RSRP/RSRQ/RSSI measurement (RRM measurement)by using the third signal.

In a case where the DRS is generated from the signals based on theplurality of structures, a signal having a specific structure istransmitted, and thus, the activated/deactivated state of the small cellmay be represented. For example, in a case where a fourth signal (asignal having a fourth structure) is transmitted, the terminal device 1may recognize that the small cell is in the activated state, and mayperform the process. That is, the terminal device 1 may recognize thatthe small cell is in the activated state by detecting the fourth signal(the signal having the fourth structure).

The CSI measurement may be performed using a fifth signal (a signalhaving a fifth structure). In a case where the CSI measurement isperformed, the terminal device 1 may perform the CSI reporting in afirst uplink subframe which is positioned after a predetermined subframefrom a subframe on which the CSI measurement is performed. The CSImeasurement may be performed using another signal instead of the fifthsignal. In a case where the CSI measurement is performed in thedeactivated state, configuration information for performing the CSImeasurement/CSI reporting in the deactivated state is notified to theterminal device 1 from the base station device 3 using the higher layersignalling.

The structure of the DRS transmitted from the small cell (base stationdevice 3 constituting the small cell) may be different between theactivated state and the deactivated state of the small cell. Forexample, the signals having the first structure to the third structuremay be transmitted in the deactivated state, and the signals having thefirst structure to the fourth structure may be transmitted in theactivated state. In the activated state, the signal having the fourthstructure instead of the signal having the third structure may betransmitted. In a case where the plurality of signals having the samestructure as that of the SSS are configured, the plurality of signalsmay be transmitted in the deactivated state of the small cell, but onlyone signal may be transmitted in the activated state of the small cell.That is, the structure of the DRS may be switched depending on the stateof the small cell.

In order to transmit an extended physical layer cell identity (PCI), theDRS may include a plurality of signals. The physical layer cell identityand the transmission point identity (TPID) may be transmitted using theplurality of signals. Here, the plurality of signals may be a pluralityof SSSs or signals having the same structure as that of the SSS. Here,the plurality of signals may be signals having the same structure asthat of the PSS and the SSS. The plurality of signals may be signalshaving the same structure as that of the PSS and the plurality of SSSs.The TPID may be a virtual cell identity (VCID). The TPID may be atransmission point, that is, an ID for identifying the base stationdevice 3. The VCID may be identity used for a signal sequence. In otherwords, due to the use of the DRS, the cell ID group is identified by thesignal having the first structure, the cell ID is identified by thesignal having the first structure and the signal having the secondstructure, and the TPID is identified by the signal having the firststructure, the signal having the second structure and the signal havingthe third structure. The TPID may be extended by the signal having thefourth structure.

The DRS may be individually configured from the PSS, the SSS, the CRS,and the CSI-RS. That is, the subframe configuration or resourceconfiguration of the DRS, the antenna port index, the number of antennaports, and the ID for sequence generation may be independently(individually) configured from the PSS, the SSS, the CRS, and theCSI-RS.

FIG. 9 is a diagram showing an example of the structure of the DRS.Here, the sequence (signal sequence or reference signal sequence) usedfor the DRS may be generated by a Zadoff-Chu sequence on the frequencyaxis. The DRSs may be successively allocated to the frequency axis. TheDRSs may be transmitted using 6 resource blocks and using 62 subcarriersof these resource blocks. The DRSs may be transmitted at zero power byusing 10 subcarriers of the 6 resource blocks. In other words, the DRSsmay reserve 10 subcarriers of the 6 resource blocks, and the signal maynot be transmitted. The DRSs are allocated to the last OFDM symbols ofthe slot number 0 and the slot number 10 in the case of the FDD (framestructure type 1), and are mapped to the third OFDM symbols of thesubframe 1 and the subframe 6 in the case of the TDD (frame structuretype 2). The DRSs may be transmitted by including a part of informationfor identifying the cell ID.

The DRSs may be allocated to resource blocks (different frequencypositions) different from that of the PSS. The DRSs may be transmittedusing the number of resource blocks different from that of the PSS. TheDRSs may be transmitted using the number of carriers different from thatof the PSS. The DRSs may be allocated to OFDM symbols different fromthose of the PSS. The DRSs may be transmitted by including informationdifferent from the cell ID (PCI or VCID).

Another example of the structure of the DRS will be described.

FIG. 9 shows another example of the structure of the DRS. The sequence(signal sequence or reference signal sequence) used for the DRS may beinterleaved by connecting two binary sequences having a length of 31.The sequence of the DRS may be generated based on an M sequence. TheDRSs are different from the signals allocated to the subframe 0 and thesignals allocated to the subframe 5. The DRSs are allocated to the sixthOFDM symbols of the slot number 0 and the slot number 10 in the case ofthe FDD, and are allocated to the seventh OFDM symbols of the slotnumber 1 and the slot number 11 in the case of the TDD. In other words,the DRSs are allocated to the second OFDM symbols from the last of theslot number 0 and the slot number 10 in the case of the FDD, and areallocated to the last OFDM symbols of the slot number 1 and the slotnumber 11 in the case of the TDD. In this case, the DRSs may betransmitted by including a part of the information for identifying thecell ID.

The DRSs may be allocated to the resource blocks (frequency positions)different from that of the SSS. The DRSs may be transmitted using thenumber of resource blocks different from that of the SSS. The DRSs maybe transmitted using the number of subcarriers different from that ofthe SSS. The DRSs may be allocated to the OFDM symbols different fromthat of the SSS. The DRSs may be transmitted by including theinformation different form the cell ID.

The number of subframes in which the DRS is transmitted is not limited.For example, the DRS may be transmitted in the subframes 0, 1, 5, and 6.That is, a plurality of DRSs based on the structure of the SSS may betransmitted. In this case, many information items may be transmitted byadding the information items to the DRS. In this case, since the numberof orthogonal sequences is increased, an effect of suppressing theinter-cell interference is obtained.

FIG. 10 shows another example of the structure of the DRS. The signal ofthe DRS is generated using a pseudo-random sequence. The pseudo-randomsequence is, for example, a Gold sequence. The pseudo-random sequence iscalculated based on the cell ID (PCI, VCID, scramble identity (ID),scrambling identity, or scrambling initialization identity (ID)). Thepseudo-random sequence is calculated based on the type of the CP. Thepseudo-random sequence is calculated based on the slot number and theOFDM symbol number within the slot. The resource elements of the DRSstransmitted through one antenna port are allocated to the frequency axisat intervals of 6 subcarriers. The resource elements of the DRSstransmitted through the antenna port p and the DRSs transmitted throughthe antenna port p+1 are allocated at intervals of 3 subcarriers. TheDRS is shifted on the frequency so as to be specific to the cell basedon the cell ID. The resource elements of the DRSs transmitted throughthe antenna port p and the DRSs transmitted through the antenna port p+1are allocated to the OFDM symbols 0 and 4 in the case of the normal CP,and are allocated to the OFDM symbols 0 and 3 in the case of theextended CP. The resource elements of the DRSs transmitted through theantenna port p+2 and the DRSs transmitted through the antenna port p+3are allocated to the OFDM symbols 1. The DRSs are transmitted in abroadband with a bandwidth configured for the downlink. The transmissionbandwidth of the DRS may be configured using the higher layersignalling. The transmission bandwidth of the DRS may be regarded asbeing the same as the measurement bandwidth.

The DRSs may be transmitted using a pseudo-random sequence differentfrom that of the CRS. The DRSs may use a sequence calculation methoddifferent form that of the CRS. The DRSs may be allocated to thefrequency at a cycle of subcarriers different from that of the CRS. Thearrangement relationship of the resource elements between the antennaport p through which the DRS is transmitted and the antenna port p+1through which the DRS is transmitted may be different from thearrangement relationship between the antenna port 0 and the antennaport 1. The arrangement of the DRSs may be shifted on the frequencybased on information different from that of the CRS. The DRSs may beallocated to OFDM symbols different from those of the CRS. The DRSs maybe allocated to a bandwidth different from that of the CRS, or may beallocated to the bandwidth configured in the higher layer, and may betransmitted in a narrowband.

FIG. 10 shows another example of the structure of the DRS. The sequences(signal sequence and reference signal sequence) of the DRSs (D1 and D2of FIG. 10) are generated using the pseudo-random sequence. Thepseudo-random sequence is, for example, a Gold sequence. Thepseudo-random sequence is calculated based on the information from thehigher layer. The pseudo-random sequence is calculated based on the cellID in a case where the information from the higher layer is notconfigured. The pseudo-random sequence is calculated based on the typeof the CP. The pseudo-random sequence is calculated based on the slotnumber and the OFDM symbol number within the slot. The resource elementsto which the DRSs are allocated may be determined by resourceconfiguration numbers (DRS resource configuration index), and may becalculated using the table of FIG. 12. Here, k′ represents a subcarriernumber, l′ represents an OFDM symbol number, n_(s) represents a slotnumber, and n_(s) mod 2 represents a slot number within a subframe. Forexample, in the case of configuration number 0, the DRSs are allocatedto the resource elements of the slot number 0, the subcarrier number 9,and the OFDM symbol numbers 5 and 6. The DRSs are transmitted in abroadband with a bandwidth configured for the downlink.

The sequence of the DRS may use a pseudo-random sequence different fromthat of the CSI-RS. The sequence of the DRS may be generated based on asequence calculation method different from that of the CSI-RS. The DRSsare not limited to the table of FIG. 12, and may be resource elementsdifferent from those of the CSI-RS. The DRSs may be allocated to abandwidth different from that of the CSI-RS, or may be allocated to thebandwidth configured in the higher layer and may be transmitted in anarrowband.

FIG. 10 shows another example of the structure of the DRS. The resourceelements to which the DRSs are allocated are determined by resourceconfiguration numbers (DRS resource configuration index), and arecalculated using the table of FIG. 12. Here, k′ represents a subcarriernumber, l′ represents an OFDM symbol number, n_(s) represents a slotnumber, and n_(s) mod 2 represents a slot number within a subframe. Forexample, in the case of the configuration number 0, the DRSs areallocated to the resource elements of the slot number 0, the subcarriernumber 9, and the OFDM symbol numbers 5 and 6. The DRSs are transmittedto a broadband with a bandwidth configured for the downlink. The DRSsmay be transmitted in the configured resource elements at zero power. Inother words, the base station device 3 may not transmit the DRSs in theconfigured resource elements. From a viewpoint of the terminal device 1,the resource elements in which the DRSs are not transmitted from thebase station device 3 may use interference measurement from theneighbour cell (or neighbour base station device). The DRSs may have thesame structure as that of R6 of FIG. 11.

FIG. 11 shows an example of the structure of the DRS. The sequence ofthe DRS is generated using a pseudo-random sequence. The pseudo-randomsequence is, for example, a Gold sequence. The pseudo-random sequence iscalculated based on the cell ID. The pseudo-random sequence iscalculated based on the type of the CP. The pseudo-random sequence iscalculated based on the slot number and the OFDM symbol number withinthe slot. The DRSs transmitted through one antenna port are allocated tothe frequency axis at a cycle of 6 subcarriers. The DRS is shifted onthe frequency based on the cell ID so as to be specific to the cell. TheDRSs are allocated to the OFDM symbols 3, 5 and 6 of the slot 0 and theOFD symbols 1, 2, 3, 5 and 6 of the slot 1 in the case of the normal CP,and are allocated to the OFDM symbols 4 and 5 of the slot 0 and the OFDMsymbols 1, 2, 4 and 5 of the slot 1 in the case of the extended CP. Theresource elements of the DRSs are allocated to a first OFDM symbols anda (1+L)-th OFDM symbols so as to be shifted on the frequency by L. TheDRSs are transmitted in a broadband with a bandwidth configured for thedownlink.

The sequence of the DRS may use a pseudo-random sequence different fromthat of PRS. The sequence of the DRS may use a sequence calculationmethod different from that of the PRS. The DRSs may be allocated to thefrequency at a cycle of subcarriers different from that of the PRS. TheDRSs may be allocated to OFDM symbols different from those of the PRS.The DRSs may be allocated to a bandwidth different from that of the PRS,and may be allocated to the bandwidth configured in the higher layer andmay be transmitted in a narrowband. That is, the transmission bandwidthor the measurement bandwidth of the DRS may be configured in the higherlayer.

The DRS may include a CSI-IM resource. The CSI-IM resource is a resourceused by the terminal device 1 to measure interference. For example, theterminal device 1 uses the CSI-IM resource as a resource for measuringinterference in the CSI measurement or a resource for measuringinterference in the RSRQ measurement. The CSI-IM resource is configuredusing the same method as the CSI-RS configuration method. The CSI-IMresource may be a resource configured as a zero power CSI-RS.

The structure of the DRS has been described above, but is not limited toonly the above-described examples, and the structure of the DRS may beachieved by combining the plurality of above-described examples.

A specific example of a preferred combination will be described. The DRSmay generated by combining the signal generated based on the Zadoff-Chusequence, the signal generated based on the M sequence and the signalgenerated based on the Gold sequence. The signal generated based on theGold sequence may be generated in a band broader than that of the signalgenerated based on the Zadoff-Chu sequence, and the signal generatedbased on the Zadoff-Chu sequence may be transmitted using 6 resourceblocks, and the signal generated based on the Gold sequence may betransmitted in the entire band of the subframe. That is, the bandwidthin which the DRS is transmitted may be configurable by the higher layer.That is, it is preferable that the DRS includes signals having differentstructures in different sequences.

The DRS may include combinations of the signal generated based on theZadoff-Chu sequence, the signal generated based on the M sequence, thesignal generated based on the Gold sequence and the signal transmittedat zero power. The signal generated based on the Gold sequence and thesignal transmitted at zero power may be designated the resource elementsby the configuration information of the DRS. The signal generated basedon the Gold sequence may be generated in a band broader than that of thesignal generated based on the Zadoff-Chu sequence, the signal generatedbased on the Zadoff-Chu sequence may be transmitted using 6 resourceblocks, and the signal based on the Gold sequence may be transmitted inthe entire band of the subframe.

The DRS configuration is notified to the terminal device 1 through thededicated RRC signaling. The configuration of the DRS includesinformation common to the cells that transmit the RS and information ofindividual information that transmits the DRS. The configuration of theDRS may be notified by being added to configuration information of ameasurement object to be described below.

The information common to the cells that transmit the DRS includesinformation of a center frequency of a band, information of a bandwidth,and information of a subframe.

The information of the individual cell that transmits the DRS includesinformation of a center frequency of a band, information of a bandwidth,information of a subframe, information for designating the resourceelement, information (cell ID, PCI, or VCID) for identifying the cell.

Since the terminal device 1 can recognize the subframe that includes theDRS by the configuration of the DRS, a DRS detection process may not beperformed in the subframe that does not include the DRS. Accordingly,the power consumption of the terminal device 1 can be reduced.

The configuration of the DRS may include a configuration of a signalhaving a first structure to a configuration of a signal having an n-thstructure. For example, the resource configurations of the signalshaving the respective structures may be individually set. The subframeconfigurations or transmission powers of the signals having therespective structures may be common (or may have a common value). Thecell ID, the antenna port index, or the number of antenna ports may beset to only a signal having a certain structure. As the configuration ofthe DRS, a plurality of resource configurations or subframeconfigurations may be set to a signal having a certain structure.

The configuration of the DRS may include information (parameter)indicating the frequency in which the DRS is transmitted.

The configuration of the DRS may include information indicating anoffset (offset value) of a subframe in which the DRS is likely to betransmitted.

The configuration of the DRS may include information indicating asubframe cycle at which the DRS is likely to be transmitted.

The configuration of the DRS may include an identifier for generatingthe sequence of the DRS.

The configuration of the DRS may include information indicating anantenna port through which the DRS is transmitted.

The configuration of the DRS may include information indicating a bursttransmission period of the DRS.

The configuration of the DRS may include information indicating asubframe cycle during which the DRS is measured once during the subframecycle.

That is, the configuration of the DRS may include information requiredto transmit the DRS, and/or information required to receive the DRS,and/or information required to measure the DRS.

The information included in the configuration of the DRS may be set foreach signal having each structure. That is, the above-describedinformation may be set to the signals having different structures.

The configuration of the DRS may be notified using the higher layersignalling. The configuration of the DRS may be notified using thesystem information. Partial information of the configuration of the DRSmay be notified using the L1 signalling (DCI format) or L2 signalling(MAC CE).

The DRS may be used for a reference signal (listening RS) forinter-base-station-device synchronization (network listening) throughthe wireless interface in the same frequency.

Hereinafter, the inter-base-station-device synchronization through thewireless interface using the DRS will be described.

The transmission timing is synchronized between the base stationdevices, and thus, the application of the TDD system, the application ofan inter-cell interference suppression technology such as eICIC or CoMP,and the application of carrier aggregation between the base stationdevices of which the transmission points are different are possible.However, in a case where the small cells are arranged in a building andan environment in which the delay of the backhaul is large, it isdifficult to perform the time synchronization by the backhaul or aglobal navigation satellite system (GSNN). Thus, a wireless interface isused to perform the synchronization of the transmission timing of thedownlink.

A procedure of the inter-base-station-device synchronization through thewireless interface will be described. Initially, the determination ofthe base station device 3 as a reference of the transmission timing andthe designation of the transmission timing of the listening RS areperformed through the backhaul. The determination of the base stationdevice 3 that performs the synchronization of the transmission timingand the designation of the reception timing of the listening RS areperformed through the backhaul. The determination of the base stationdevice 3 as the reference of the transmission timing, the base stationdevice 3 that performs the synchronization of the transmission timing,and the transmission/reception timing of the listening RS may beperformed by the base station device, the MME or the S-GW. The basestation device 3 as the reference of the transmission timing transmitsthe listening RS in the downlink component carrier or the downlinksubframe based on the transmission timing notified through the backhaul.The base station device 3 that performs the synchronization of thetransmission timing receives the listening RS at the notified receptiontiming, and performs the synchronization of the transmission timing. Thelistening RS may be transmitted even in the deactivated state of thebase station device 3 as the reference of the transmission timing. Thelistening RS may be received even in the activated/deactivated state ofthe base station device 3 that performs the synchronization of thetransmission timing.

In the TDD, the base station device 3 that performs the synchronizationof the transmission timing stops transmitting the downlink signal duringwhich the listening RS is received, and performs the reception processof the radio signal. In other words, the base station device 3 thatperforms the synchronization of the transmission timing is configured inthe uplink subframe during which the listening RS is received. Here, theterminal device 1 connected to the base station device 3 that performsthe synchronization of the transmission timing recognizes that the basestation device 3 that performs the synchronization of the transmissiontiming is in the deactivated state during which the listening RS isreceived. That is, the terminal device 1 recognizes that the PSS/SSS,the PBCH, the CRS, the PCFICH, the PHICH and the PDCCH are nottransmitted from the base station device 3 that performs thesynchronization of the transmission timing. The terminal device 1 isnotified of a timing when the listening RS is received from the basestation device 3. In other words, the terminal device 1 is notified ofthe deactivated state from the base station device 3. The terminaldevice 1 does not perform the measurement on the base station device 3at the timing when the listening RS is received. The terminal device 1connected to the base station device 3 that performs the synchronizationof the transmission timing may recognize that a period during which thebase station device 3 that performs the synchronization of thetransmission timing receives the listening RS is the uplink subframe.

In the FDD, the base station device 3 that performs the synchronizationof the transmission timing stops transmitting the downlink signal duringwhich the listening RS is received, and performs the reception processusing the downlink component carrier. Here, the terminal device 1connected to the base station device 3 that performs the synchronizationof the transmission timing recognizes that the base station device 3that performs the synchronization of the transmission timing is in thedeactivated state during which the listening RS is received. That is,the terminal device 1 recognizes that the PSS/SSS, the PBCH, the CRS,the PCFICH, the PHICH and the PDCCH are not transmitted from the basestation device 3 that performs the synchronization of the transmissiontiming. The terminal device 1 is notified of the timing when thelistening RS is received from the base station device 3. In other words,the terminal device 1 is notified of the deactivated state from the basestation device 3. The terminal device 1 does not perform the measurementon the base station device 3 at the timing when the listening RS isreceived.

The terminal device 1 may detect the cell by using the listening RStransmitted from the base station device 3 as the reference of thetransmission timing.

Hereinafter, the details of the measurement of the physical layer willbe described. The terminal device 1 performs the measurement of thephysical layer to be reported to the higher layer. As the measurement ofthe physical layer, there are reference signal received power (RSRP),received signal strength indicator (RSSI), and reference signal receivedquality (RSRQ).

Hereinafter, the details of the RSRP will be described. The RSRP isdefined as the reception power of the reference signal. The RSRQ isdefined as the reception quality of the reference signal.

An example of the RSRP will be described.

The RSRP is defined as a value acquired by performing linear mean onpower of the resource element to which the CRS included in a measurementfrequency bandwidth to be considered is transmitted. In thedetermination of the RSRP, the resource element to which the CRS of theantenna port 0 is mapped is used. If the terminal device can detect theCRS of the antenna port 1, it is possible to use the resource element(the radio resource mapped to the resource element assigned to theantenna port 1) to which the CRS of the antenna port 1 is mapped inaddition to the resource element (the radio resource mapped to theresource element assigned to the antenna port 0) to which the CRS of theantenna port 0 is mapped in order to determine the RSRP. Hereinafter,the RSRP calculated using the resource element to which the CRS of theantenna port 0 is mapped is referred to as a CRS base RSRP or a firstRSRP.

The terminal device 1 measures the RSRP of the cell having anintra-frequency and/or the cell having an inter-frequency in an RRC idle(RRC_IDLE). Here, the cell having the inter-frequency in the RRC idlestate is a cell having the same frequency band as that of the cell fromwhich the terminal device receives the system information through thebroadcasting. Here, the cell having the inter-frequency in the RRC idlestate is a cell having a frequency band different from that of the cellfrom which the terminal device 1 receives the system information throughthe broadcasting. The terminal device 1 measures the RSRP of the cellhaving the intra-frequency and/or the cell having the inter-frequency inthe RRC connected (RRC_CONNECTED) state. Here, the cell having theintra-frequency in the RRC connected state is a cell having the samefrequency band as that of the cell from which the terminal device 1receives the system information through the RRC signaling or thebroadcasting. Here, the cell having the inter-frequency in the RRCconnected state is a cell having a frequency band different from that ofthe cell from which the terminal device 1 receives the systeminformation through the RRC signaling or the broadcasting.

An example of the RSRP will be described.

The RSRP is defined as a value acquired by performing linear mean onpower of the resource element to which the DRS included in a measurementfrequency bandwidth to be considered is transmitted. In the measurementof the RSRP, the resource element to which the DRS is mapped is used.The resource element and the antenna port to which the DRS istransmitted is notified in the higher layer are used.

The terminal device 1 measures the RSRP of the cell having theintra-frequency and/or the cell having the inter-frequency in the RRCconnected (RRC_CONNECTED) state.

The details of the RSSI will be described. The RSSI is defined by totalreception power observed using a receive antenna.

An example of the RSSI will be described.

The RSSI (E-UTRA carrier RSSI) includes a value acquired by performinglinear mean on total reception power acquired by observing only the OFDMsymbol including the reference signal of the antenna port 0. In otherwords, the RSSI includes a value acquired by performing linear mean onthe total reception power acquired by observing only the OFDM symbolincluding the CRS of the antenna port 0. The RSSI is observed in abandwidth of the number of resource blocks N. The total reception powerof the RSSI includes power from the serving cell or the non-serving cellon the same channel, interference power from the neighbour channel, andthermal noise power.

An example of the RSSI will be described.

The RSSI (E-UTRA carrier RSSI) includes a value acquired by performinglinear mean on total reception power acquired by observing all the OFDMsymbols. The total reception power of the RSSI includes power from theserving cell or the non-serving cell on the same channel, interferencepower from the neighbour channel, and thermal noise power.

An example of the RSSI will be described.

The RSSI (E-UTRA carrier RSSI) includes a value acquired by performinglinear mean on total reception power acquired by observing the OFDMsymbols that do not include the DRS. The RSSI is observed in a bandwidthof the number of resource blocks N. The total reception power of theRSSI includes power from the serving cell or the non-serving cell on thesame channel, interference power from the neighbour channel, and thermalnoise power. The resource element and/or the antenna port to which theDRS is transmitted are notified in the higher layer.

An example of the RSSI will be described.

The RSSI (E-UTRA carrier RSSI) includes a value acquired by performinglinear mean on total reception power acquired by observing only the OFDMsymbols that do not include the DRS (CRS and/or CSI-RS). In other words,the RSSI includes a value acquired by performing linear mean on totalreception power acquired by observing the OFDM symbols that do notinclude the DRS (CRS and/or CSI-RS). The RSSI is observed in a bandwidthof the number of resource blocks N. The total reception power of theRSSI includes power from the serving cell or the non-serving cell on thesame channel, interference power from the neighbour channel, and thermalnoise power.

An example of the RSSI will be described.

The RSSI (E-UTRA carrier RSSI) includes a total value of a valueacquired by performing total reception power acquired by observing onlythe OFDM symbols that do not include the DRS (CRS and/or CSI-RS) and avalue of the RSRP. In other words, the RSSI includes a total value of avalue acquired by performing linear mean on total reception poweracquired by observing only the OFDM symbols that do not include the DRS(CRS and/or CSI-RS) and a value of the RSRP. The RSSI is observed in abandwidth of the number of resource blocks N. The total reception powerof the RSSI includes power from the serving cell or the non-serving cellon the same channel, interference power from the neighbour channel, andthermal noise power.

Hereinafter, the details of the RSRQ will be described. The RSRQ isdefined as a ratio between the RSRP and the RSSI, and is used for thesame purpose as that of a signal-to-interference-plus-noise ratio (SINR)of a measuring target cell which is an index of communication quality.The combination of the RSRP and the RSSI in the RSRQ is not limited tothe following combination. However, in the present embodiment, apreferred combination of the RSRP and the RSSI in the RSRQ is described.

An example of the RSRQ will be described.

The RSRQ is defined as a ratio calculated by the expression ofN×RSRP/RSSI. Here, N is the number of resource blocks equivalent to themeasurement bandwidth of the RSSI, and the numerator and denominator ofthe RSRQ include the set of the same resource block. Here, the RSRP is afirst RSRP. Hereinafter, the RSRQ calculated using the RSRQ calculatedusing the first RSRP is referred to as a CRS base RSRQ or a first RSRQ.

The RSSI (E-UTRA carrier RSSI) includes a value acquired by performinglinear mean on total reception power acquired by observing only the OFDMsymbols that include the reference signal of the antenna port 0. Inother words, the RSSI includes a value acquired by performing linearmean on total reception power acquired by observing only the OFDMsymbols that include the CRS (the radio resource mapped to the antennaport 0) of the antenna port 0. The RSSI is observed in a bandwidth ofthe number of resource blocks N. The total reception power of the RSSIincludes power from the serving cell or the non-serving cell on the samechannel, interference power from the neighbour channel, and thermalnoise power. In a case where a predetermined subframe for measuring theRSRQ is designated from the signalling of the higher layer, the RSSI ismeasured from all the OFDM symbols in the designated subframe.

The terminal device 1 measures the RSRQ of the cell having theintra-frequency and/or the cell having the inter-frequency in the RRCidle state. The terminal device 1 measures the RSRQ of the cell havingthe intra-frequency and/or the cell having the inter-frequency in theRRC connected state.

An example of the RSRQ will be described.

The RSRQ is defined as a ratio calculated by the expression ofN×RSRP/RSSI. Here, N is the number of resource blocks of the measurementbandwidth of the RSSI, and the numerator and denominator of the RSRQneed to include the set of the same resource block. Here, the RSRP is asecond RSRP. Hereinafter, the RSRQ calculated using the RSRQ calculatedusing the second RSRP is referred to as a second RSRQ.

The RSSI (E-UTRA carrier RSSI) includes a value acquired by performinglinear mean on total reception power acquired by observing only the OFDMsymbols including the reference signal of the antenna port 0. In otherwords, the RSSI includes a value acquired by performing linear mean ontotal reception power acquired by observing only the OFDM symbols thatinclude the CRS of the antenna port 0. The RSSI is observed in abandwidth of the number of resource blocks N. The total reception powerof the RSSI includes power from the serving cell or the non-serving cellon the same channel, interference power from the neighbour channel, andthermal noise power. In a case where a predetermined subframe formeasuring the RSRQ is designated from the signalling of the higherlayer, the RSSI is measured from all the OFDM symbols in the designatedsubframe.

An example of the RSRQ will be described.

The RSRQ is defined as a ratio calculated by the expression ofN×RSRP/RSSI. Here, N is the number of resource blocks equivalent to themeasurement bandwidth of the RSSI, and the numerator and denominator ofthe RSRQ are constituted by a set of same resource blocks. Here, theRSRP is measured based on the DRS (CRS and/or CSI-RS).

The RSSI (E-UTRA carrier RSSI) includes a total value of a valueacquired by performing linear mean on total reception power acquired byobserving only the OFDM symbols that do not include the DRS (CRS and/orCSI-RS) and a value of the RSRP. In other words, the RSSI includes atotal value of a value acquired by performing linear mean on totalreception power acquired by observing only the OFDM symbols that do notinclude the DRS (CRS and/or CSI-RS) and a value of the RSRP. The RSSI isobserved in a bandwidth of the number of resource blocks N. The totalreception power of the RSSI includes power from the serving cell or thenon-serving cell on the same channel, interference power from theneighbour channel, and thermal noise power.

The RSSI used for the RSRQ may be acquired based on the RSRP and thelinear mean value of the total reception power acquired by the OFDMsymbols that do not include the DRS within the measurement bandwidth.

The RSSI used for the RSRQ may be acquired from the linear mean value ofthe total reception power acquired by all the OFDM symbols of themeasurement bandwidth.

The RSSI used for the RSRQ may be acquired from the linear mean value ofthe total reception power acquired by the OFDM symbols that do notinclude the DRS within the measurement bandwidth.

The RSSI used for the RSRQ may be acquired from the RSSI measurement onthe CRS constituting the DRS.

In a case where the DRS has the same structure as that of the CSI-RS, 5MHz or more may be configured as the measurement bandwidth.

In a case where the DRS has the same structure as that of the CSI-RS, 6RBs and/or 15 RBs may be configured for the measurement bandwidth.

The measurement bandwidth of the DRS may be configured using the higherlayer signalling.

The terminal device 1 measures the RSRQ of the cell having theintra-frequency and/or the cell having the inter-frequency in the RRCconnected state.

A first measurement procedure will be described. First measurement is tomeasure the first RSRP or the first RSRQ. The first measurement may bethe measurement (RRM measurement, RSRP measurement, RSRQ measurement orRSSI measurement) of the first signal (the signal having the firststructure).

The terminal device 1 recognizes the resource elements to which the CRSstransmitted though the antenna port 0 from the physical cell identity(PCI) are allocated. The terminal device measures the first RSRP fromthe resource elements to which the CRSs transmitted through the antennaport 0 are allocated. The number of subframes used in the measurement isnot limited, and the measurement may be performed over a plurality ofsubframes, and the average value may be reported. Subsequently, theterminal device recognizes the OFDM symbols including the antenna port0, and measures the RSSI. The first RSRQ is calculated from the firstRSRP and RSSI. The measurement subframes of the first RSRP and RSSI maybe different.

The result (the first RSRP or the first RSRQ) acquired based on thefirst measurement procedure is referred to as a first measurementresult.

A second measurement procedure will be described. Second measurement isto measure the second RSRP or the second RSRQ.

The terminal device 1 recognizes the resource elements to which the DRSsare allocated from the configuration information of the DRS. Theterminal device measures the second RSRP from the resource elements towhich the DRSs are allocated. The number of subframes used in themeasurement is not limited, and the measurement may be performed on theplurality of subframes, and the average value thereof may be reported.Subsequently, the RSSI is measured. The second RSRQ is calculated fromthe second RSRP and RSSI.

The result (the second RSRP, the second RSRQ, the second RSSI or thesecond RRM) acquired based on the second measurement procedure isreferred to a second measurement result. The second measurement may bethe measurement (the RRM measurement, the RSRP measurement, the RSRQmeasurement or the RSSI measurement) of the second signal (the signalhaving the second structure).

Hereinafter, the mechanism for reporting the measurement value measuredby the terminal device 1 to the higher layer will be described.

A measurement model will be described. FIG. 13 is a diagram showing anexample of the measurement model.

A measurement unit 1301 may include a Layer 1 filtering unit 13011, aLayer 3 filtering unit 13012, and a report criteria evaluation unit13013. The measurement unit 1301 may have a partial function of thereception unit 105 and the higher layer processing unit 101.Specifically, the Layer 1 filtering unit 13011 may be included in thereception unit 105, and the Layer 3 filtering unit 13012 and the reportcriteria evaluation 13013 may be included in the higher layer processingunit 101.

A filter is applied to the measurement value (sample) input from thephysical layer by the Layer 1 filtering unit 13011. For example, theLayer 1 filtering unit 13011 may apply the mean of a plurality of inputvalues, the weighted mean, the mean according to the channelcharacteristics, or may apply other filtering methods. Measurement valuereported from the first layer is input to the third layer after theLayer 1 filtering unit 13011. The filter is applied to the measurementvalue input to the Layer 3 filtering unit 13012. The configuration ofthe Layer 3 filtering is provided from the RRC signaling. An interval atwhich the measurement value is filtered by the Layer 3 filtering unit13012 and is reported is the same as that of the input measurement gap.The report criteria evaluation unit 13013 checks whether or not thereporting of the measurement value is actually required. The evaluationis based on one or more measurement flows. For example, the evaluationis the comparison of different measurement values. The terminal device 1evaluates the report criteria at least whenever a new measurement resultis reported. The configuration of the report criteria is providedthrough the RRC signaling. After it is determined that the reporting ofthe measurement value is required in the evaluation of the reportcriteria, the terminal device 1 sends measurement report information(measurement report message) through the wireless interface.

Hereinafter, the measurement will be described. The base station device3 transmits a measurement configuration message to the terminal device 1by using a RRC connection reconfiguration message of the RRC signaling(radio resource control signal). The terminal device 1 configures thesystem information included in the measurement configuration message,and performs measurement, event evaluation and measurement reporting onthe serving cell and the neighbour cell (including a listed cell and/ora detected cell) according to the notified system information. Thelisted cell is a cell (a cell notified as a neighbour cell list of theterminal device 1 from the base station device 3) listed as ameasurement object, and the detected cell is a cell (a cell which is notnotified as the neighbour cell list and is detected by the terminaldevice 1) which is detected by the terminal device 1 in the frequencyindicated by the measurement object but is not listed as the measurementobject.

As the measurement, there are three types (intra-frequency measurements,inter-frequency measurements, and inter-RAT measurements). Theintra-frequency measurements are measurements in the downlink frequencyof the serving cell. The inter-frequency measurements are measurementsin a frequency different from the downlink frequency of the servingcell. The inter-RAT measurements are measurements in the radiotechnology (for example, UTRA, GERAN or CDMA2000) different from theradio technology (for example, EUTRA) of the serving cell.

The measurement configuration message includes a measurement identity(measId), measurement objects, and the addition and/or the modificationand/or the removing of the configurations of the reportingconfigurations, physical quantity configuration (quantityConfig),measurement gap configuration (measGapConfig), and serving cell qualitythreshold (s-Measure).

The physical quantity configuration (quantityConfig) designates a L3filtering coefficient in a case where the measurement objects are EUTRA.The L3 filtering coefficient defines a ratio between the latestmeasurement result and the past filtering measurement result. Thefiltering result is used in the event evaluation by the terminal device1.

The measurement gap configuration (measGapConfig) is used for theconfiguration of a measurement gap pattern or theactivation/deactivation of a measurement gap. In the measurement capconfiguration (measGapConfig), a gap pattern, a start system framenumber (startSFN), or a start subframe number (startSubframeNumber) isnotified as information in a case where the measurement gap isactivated. The gap pattern defines a pattern to be used as themeasurement gap. The start system frame number (startSFN) defines asystem frame number (SFN) in which the measurement gap is started. Thestart subframe number (startSubframeNumber) defines a subframe number inwhich the measurement gap is started.

In a case where the uplink/downlink transmission is not scheduled, themeasurement gap is a period (time or subframe) that is likely to be usedby the terminal device 1 to perform the measurement.

In a case where the measurement gap is configured for the terminaldevice 1 (or to which the DRS configuration is set) that supports themeasurement of the DRS, the measurement of the DRS may be performed inthe subframe (that is, on the measurement gap) defined based on themeasurement gap configuration.

In a case where the measurement gap is configured for the terminaldevice 1 (or to which the DRS configuration is set) that supports themeasurement of the DRS, the DRS may be measured on the measurement gapif the DRS transmission subframe based on the subframe configurationincluded in the DRS configuration overlaps with the subframe definedbased on the measurement gap configuration. If the DRS transmissionsubframe is present on the measurement gap, the terminal device 1 maymeasure the DRS on the measurement gap.

In a case where the measurement gap is configured for the terminaldevice 1 (or to which the DRS configuration is set) that supports themeasurement of the DRS, the DRS may be measured for only the cell in thedeactivated state on the measurement gap in the DCI format or the MACCE. That is, the terminal device 1 may not perform the measurement ofthe DRS on the cell in the activated state on the measurement gap. Thebase station device 3 may not transmit the DRS in the cell in theactivated state.

The measurement gap may be configured for each DRS or each cell in theactivated/deactivated state.

The serving cell quality threshold (s-Measure) represents a thresholdrelated to the quality of the serving cell, and is used by the terminaldevice 1 to control whether or not it is necessary to perform themeasurement. The serving cell quality threshold (s-Measure) isconfigured as a value of the RSRP.

Here, the measurement identity (measId) is used to link the measurementobjects and the reporting configurations, and specifically, to link themeasurement object identity (measObjectId) and the reportingconfiguration identity (reportConfigId). One measurement object identity(measObjectId) and one reporting configuration identity (reportConfigId)are correlated with the measurement identity (measId). The measurementconfiguration message may be added, modified and removed for therelationship between the measurement identity (measId), the measurementobjects and the reporting configurations.

measObjectToRemoveList is a command for removing the measurement objectscorresponding to the designated measurement object identity(measObjectId) and the designated measurement object identity(measObjectId). In this case, all the measurement identity (measId)correlated with the designated measurement object identity(measObjectId) are removed. This command can simultaneously designate aplurality of measurement object identities (measObjectIds).

measObjectToAddModifyList is a command for modifying the designatedmeasurement object identities (measObjectIds) to the designatedmeasurement objects or adding the designated measurement objectidentities (measObjectIds) and the designated measurement objects(measurement objects). This command can simultaneously designate aplurality of measurement object identities (measObjectIds).

reportConfigToRemoveList is a command for removing the reportingconfigurations corresponding to the designated reporting configurationidentity (reportConfigId) and the designated reporting configurationidentity (reportConfigId). In this case, all the measurement identities(measIds) correlated with the designated reporting configurationidentity (reportConfigId) are removed. This command can simultaneouslydesignate a plurality of reporting configuration identities(reportConfigIds).

measIdToRemoveList is a command for removing the designated measurementidentity (measId). In this case, the measurement object identity(measObjectId) and the reporting configuration identity (reportConfigId)correlated with the designated measurement identity (measId) aremaintained without being removed. This command can simultaneouslydesignate a plurality of measurement identities (measIds).

measIdToAddModifyList is a command for modifying the designatedmeasurement identity (measId) such that the measurement identity iscorrelated with the designated measurement object identity(measObjectId) and the designated reporting configuration identity(reportConfigId) or adding the designated measurement identity (measId)by correlating the designated measurement object identity (measObjectId)and the designated reporting configuration identity (reportConfigId)with the designated measurement identity (measId). This command cansimultaneously designate a plurality of measurement identities(measIds).

The measurement objects are defined for each radio access technology(RAT) and frequency. As the reporting configurations, there are thedefinition of the EUTRA and the definition of the RAT other than theEUTRA.

The measurement object includes measurement object EUTRA(measObjectEUTRA) correlated with the measurement object identity(measObjectId).

The measurement object identity (measObjectId) is identity used toidentify the configuration of the measurement object. As describedabove, the configuration of the measurement object is defined for eachradio access technology (RAT) and frequency. The measurement object isseparately specified for the EUTRA, the UTRA, the GERAN or the CDMA2000.The measurement object EUTRA (measObjectEUTRA) which is the measurementobject of the EUTRA defines information applied to the neighbour cell ofthe EUTRA. The measurement object EUTRA (measObjectEUTRA) having adifferent frequency is treated as a different measurement object, and isseparately assigned the measurement object identity (measObjectId).

An example of the information of the measurement object will bedescribed.

The measurement object EUTRA (measObjectEUTRA) includes EUTRA carrierfrequency information (eutra-CarrierInfo), a measurement bandwidth(measurementBandwidth), antenna port 1 presence information(presenceAntennaPort1), an offset frequency (offsetFreq), informationrelated to a neighbour cell list, and information related to ablacklist.

Hereinafter, information included in the measurement object EUTRA(measObjectEUTRA) will be described. The EUTRA carrier frequencyinformation (eutra-CarrierInfo) designates a carrier frequency as themeasurement object. The measurement bandwidth (measurementBandwidth)indicates a measurement bandwidth common to all the neighbour cellsoperated in the carrier frequency as the measurement object. The antennaport 1 presence information (presenceAntennaPort1) indicates whether ornot the antenna port 1 is used in the cell as the measurement object.The offset frequency (offsetFreq) indicates a measurement offset valueapplied in the frequency as the measurement object.

An example of the information of the measurement object will bedescribed.

The base station device 3 performs a configuration different from thatin the first measurement for the terminal device 1 in order to performthe second measurement. For example, a signal (or the structure of thesignal, or the configuration of the signal) as the measurement objectmay be different between the first measurement and the secondmeasurement. A cell ID set to the signal as the measurement object maybe different between the first measurement and the second measurement.An antenna port of the signal as the measurement object may be differentbetween the first measurement and the second measurement. A measurementcycle (or measurement subframe pattern) of the signal as the measurementobject may be different between the first measurement and the secondmeasurement. That is, the first measurement and the second measurementmay be individually configured.

The measurement object EUTRA (measObjectEUTRA) includes EUTRA carrierfrequency information (eutra-CarrierInfo), a measurement bandwidth(measurementBandwidth), DRS configuration information, an offsetfrequency (offsetFreq), information related to a neighbour cell list,and information related to a blacklist.

Hereinafter, information included in the measurement object EUTRA(measObjectEUTRA) will be described. The EUTRA carrier frequencyinformation (eutra-CarrierInfo) designates a carrier frequency as themeasurement object. The measurement bandwidth (measurementBandwidth)indicates a measurement bandwidth common to all the neighbour cellsoperated in the carrier frequency as the measurement object. The DRSconfiguration information is used to notify the terminal device 1 of thecommon configuration information in the frequency band required todetect the DRS configuration, and indicates, for example, a subframenumber or a subframe cycle transmitted in the cell as the measurementtarget. The offset frequency (offsetFreq) indicates a measurement offsetvalue applied in the frequency as the measurement target.

An example of the information related to the neighbour cell list and theblacklist will be described.

The information related to the neighbour cell list includes informationrelated to the neighbour cell as an object of the event evaluation orthe measurement reporting. The information related to the neighbour celllist includes a physical cell identity (physical cell ID), and a cellspecific offset (cellIndividualOffset) (indicating the measurementoffset value applied to the neighbour cell). In the case of the EUTRA,this information is used as information for performing the adding,modifying or removing of the neighbour cell list already acquired frombroadcast information (broadcasted system information) by the terminaldevice 1.

The information related to the blacklist includes information related tothe neighbour cell which is not the object of the event evaluation orthe measurement reporting. The information related to the blacklistincludes the physical cell identity (physical cell ID). In the case ofthe EUTRA, this information is used as information for performing theadding, modifying or removing of the blacklisted cell list alreadyacquired from the broadcast information by the terminal device 1.

An example of the information related to the neighbour cell list and theblacklist will be described.

In a case where the second measurement is performed, it is assumed thata case where it is insufficient with the physical cell identity (PCI) isused. Thus, a new neighbour cell list and a new blacklist acquired byextending the physical cell identity are required.

Information related to the new neighbour cell list neighbour small celllist may include information related to the neighbour cell as the objectof the event evaluation or the measurement report. The informationrelated to the new neighbour cell list may include a cell ID, acell-specific offset (cellIndividualOffset) (indicating the measurementoffset applied to the neighbour cell), and cell-specific DRSconfiguration information. Here, the cell-specific DRS configurationinformation is information of the DRS configured so as to be specific tothe cell, and is, for example, information indicating the resourceelement of the used DRS. In the case of the EUTRA, this information isused as information for performing the adding, modifying or removing ofthe new neighbour cell list already acquired from the broadcastinformation (broadcasted system information) by the terminal device 1.

The information related to the new blacklist may include informationrelated to the neighbour cell that is not the object of the eventevaluation or the measurement report. The information related to the newblacklist may include the cell ID. In the case of the EUTRA, thisinformation is used as information for performing the adding, modifyingor removing of a new blacklisted cell list (blacklisted small cell list)already acquired from the broadcast information by the terminal device1.

Here, the cell ID is, for example, a physical cell ID (physical layercell ID), a cell global identity/identifier (CGI), an E-UTRAN cellglobal identifier/identity (ECGI), a discovery ID, a virtual cell ID, ora transmission point ID, and is constituted based on information of thecell (transmission point) ID transmitted by the DRS. A parameter relatedto a sequence generator (a scrambling sequence generator or apseudo-random sequence generator) may be used instead of the cell ID.

In a case where the cell ID (or the parameter (for example, thescrambling ID) related to the pseudo-random sequence generator) isincluded in the configuration of the DRS, the neighbour cell list mayindicate the list of the DRS. That is, the terminal device 1 may performthe measurement of the DRS of the cell ID set to the neighbour celllist.

In the cell ID is included in the configuration of the DRS, theblacklist may indicate the blacklist of the DRS. That is, the terminaldevice 1 may not perform the measurement of the DRS of the cell ID setto the blacklist.

Hereinafter, the details of the reporting configurations will bedescribed.

The reporting configurations include reporting configuration EUTRA(reportConfigEUTRA) correlated with the reporting configuration identity(reportConfigId).

The reporting configuration identity (reportConfigId) is identity usedto identify the reporting configurations related to the measurement. Asstated above, as the reporting configurations related to themeasurement, there are the definition for the EUTRA and the definitionfor the RAT (UTRA, GERAN, or CDMA2000) other than the EUTRA. Thereporting configuration EUTRA (reportConfigEUTRA) which is the reportingconfigurations for the EUTRA defines triggering criteria of the eventused to report the measurement in the EUTRA.

The reporting configuration EUTRA (reportConfigEUTRA) includes an eventidentity (eventId), triggering quantity (triggerQuantity), hysteresis,trigger time (timeToTrigger), reporting quantity (reportQuantity), themaximum number of reported cells (maxReportCells), reporting interval(reportInterval) and reporting amount (reportAmount).

The event identity (eventId) is used to select criteria related to theevent triggered reporting. Here, in a case where the triggering criteriaare satisfied, the event triggered reporting is a method of reportingthe measurement. In addition, in a case where the triggering criteriaare satisfied, there is event triggered periodic reporting for reportingthe measurement a certain number of times at regular intervals.

In a case where the event triggered criteria designated by the eventidentity (eventId) are satisfied, the terminal device 1 reports themeasurement to the base station device 3. The triggering quantity(triggerQuantity) is a quantity used to evaluate the event triggeredcriteria. That is, the RSRP or the RSRQ is designated. That is, theterminal device 1 measures the downlink reference signal by using thequantity designated by the triggering quantity (triggerQuantity), anddetermines whether or not the event triggered criteria designated by theevent identity (eventId) are satisfied.

The hysteresis is a parameter used in the event triggered criteria. Thetriggering time (timeToTrigger) indicates a period during which theevent triggered criteria are satisfied. The reporting quantity(reportQuantity) indicates a quantity reported by the measurementreport. Here, the quantity designated by the triggering quantity(triggerQuantity), or the RSRP and RSRQ is designated.

The maximum number of reported cells (maxReportCells) indicates themaximum number of cells included in the measurement report. Thereporting interval (reportInterval) is used in periodic reporting orevent triggered periodic reporting, and the periodical reporting isperformed every interval indicated by the reporting interval(reportInterval). The reporting amount (reportAmount) is defined by thenumber of times the periodical reporting is performed if necessary.

A threshold parameter or an offset parameter used in the event triggeredcriteria to be described below together with the event identity(eventId) is notified to the terminal device 1 in the reportingconfigurations.

The base station device 3 may or may not notify of a serving cellquality threshold (s-Measure) in some cases. In a case where the basestation device 3 notifies the serving cell quality threshold(s-Measure), when the RSRP of the serving cell is lower than the servingcell quality threshold (s-Measure), the terminal device 1 performs theevent evaluation (referred to as evaluation of reporting criteria ofwhether or not the event triggered criteria are satisfied). Meanwhile,in a case where the base station device 3 does not notify of the servingcell quality threshold (s-Measure), the terminal device 1 performs themeasurement of the neighbour cell and the event evaluation irrespectiveof the RSRP of the serving cell.

Hereinafter, the details of the event and the event triggered criteriawill be described.

The terminal device 1 that satisfies the event triggered criteriatransmits the measurement report to the base station device 3. Themeasurement report includes a measurement result.

A plurality of event triggered criteria for perform the measurementreport is defined, and there are a subscription criterion and aseparation criterion. That is, the terminal device 1 that satisfies thesubscription criterion to the event designated from the base stationdevice 3 transmits the measurement report to the base station device 3.In a case where the event separation criterion is satisfied, theterminal device 1 which satisfies the event subscription criterion andtransmits the measurement report stops transmitting the measurementreport.

An example of the event and the event triggered criterion to bedescribed below is used by any one of a first measurement result or asecond measurement result.

Hereinafter, an example of a method of designating the type ofmeasurement result used to evaluate the event triggered criteria will bedescribed.

The type of measurement result used to evaluate the event triggeredcriteria is designated by the reporting configurations. The eventtriggered criteria is evaluated using any one of the first measurementresult or the second measurement result by the parameter.

As a specific example, whether the first measurement result or thesecond measurement result is used is designated by the triggeringphysical quantity (triggerQuantity). As the triggering physicalquantity, four selection fields of {first RSRP, first RSRQ, second RSRPand second RSRQ} may be designated. The terminal device 1 measures thedownlink reference signal by using the physical layer designated by thetriggering quantity (triggerQuantity), and determines whether or not theevent triggered criteria designated by the event identity (eventId) aresatisfied.

As a specific example, whether the first measurement result or thesecond measurement result is used may be defined by a new parameter(triggerMeasType) for designating the type of measurement result used toevaluate the event triggered criteria in addition to the triggeringphysical quantity. Information indicating that the event triggeredcriteria are evaluated using the first measurement result or informationindicating that the event triggered criteria are evaluated using thesecond measurement result is set to the new parameter. For example, in acase where the information indicating that the event triggered criteriaare evaluated using the second measurement result is set to the newparameter, the terminal device 1 performs the second measurement, andevaluates the event triggered criteria by using the second measurementresult. The parameter may be shared with a parameter (reportMeasType)for designating the type of reported measurement result.

In the event triggered criteria in which two or more measurement resultsare used in one conditional expression such as comparison of themeasurement result of the serving cell and the measurement result of thesurrounding cell, the type of measurement result used to evaluate theevent triggered criteria may be designated. For example, a new parameter(triggerMeasTypeServ) for the measurement result of the serving cell anda new parameter (triggerMeasTypeNeigh) for the measurement result of thesurrounding cell may be defined.

Hereinafter, an example of the method of designating the type of themeasurement result used to evaluate the event triggered criteria will bedescribed.

The type of measurement result used to evaluate the event triggeredcriteria is determined depending on criteria for designating themeasurement by the reporting configurations.

As a specific example, the type of measurement result used to evaluatethe event triggered criteria is determined depending on theactivated/deactivated state of the target cell. For example, if thetarget cell is in the activated state, the event triggered criteria areevaluated using the first measurement result, and if the target cell isin the deactivated state, the event triggered criteria are evaluatedusing the second measurement result.

As a specific example, the type of measurement result used to evaluatethe event triggered criteria is determined depending on the detection ofthe reference signal. For example, in a case where the CRS is detectedand the DRS is not detected, the event triggered criteria may beevaluated using the first measurement result, and in a case where theCRS is not detected and the DRS is detected, the event triggeredcriteria may be evaluated using the second measurement result. In a casewhere both the CRS and the DRS are detected, the event triggeredcriteria may be evaluated using the measurement result of which thereception power is higher. In a case where both the CRS and the DRS areadetected, the event triggered criteria may be evaluated using themeasurement result acquired by averaging both the reception powers. In acase where both the CRS and the DRS are not detected, the eventtriggered criteria may not be evaluated.

Hereinafter, the details of the measurement result will be described.

The measurement result includes a measurement identity (measId), aserving cell measurement result (measResultServing), and a EUTRAmeasurement result list (measResultListEUTRA). Here, the EUTRAmeasurement result list (measResultListEUTRA) includes a physical cellidentity (physicalCellIdentity) and a EUTRA cell measurement result(measResultEUTRA). Here, as mentioned above, the measurement identity(measId) is identity used to link measurement object identity(measObjectId) and reporting configuration identity (reportConfigId).The physical cell identity (physicalCellIdentity) is used to identifythe cell. EUTRA cell measurement result (measResultEUTRA) is ameasurement result for the EUTRA cell. The measurement result of theneighbour cell is included only when the associated event occurs.

An example of the measurement result will be described.

The terminal device 1 may report the measurement result by adding theresults of the RSRP and the RSRQ for the target cell to the measurementresult. The RSRP and the RSRQ reported once may be one of the firstmeasurement result and the second measurement result. The firstmeasurement result may be a measurement result acquired from the firstmeasurement. The second measurement result may be a measurement resultacquired from the second measurement. In other words, the firstmeasurement result is a measurement result acquired based onconfiguration information related to the first measurement, and thesecond measurement result is a measurement result acquired based onconfiguration information related to the second measurement.

As a specific example, the measurement result is reported based on theparameter for determining the first measurement result or the secondmeasurement result. A reference for determining the first measurementresult or the second measurement result is, for example, a new parameter(reportMeasType). Information indicating that the first measurementresult is reported or information indicating that the second measurementresult is reported may be set to the new parameter. For example, in acase where the information indicating that the second measurement resultis reported is set to the new parameter, the terminal device 1recognizes the new parameter, performs the second measurement, transmitsthe second measurement result by adding the second measurement result tothe measurement reporting message, and does not transmit the firstmeasurement result. Information indicating that the first measurementresult and the second measurement result are reported may be set to thenew parameter.

The new parameter may be shared with a parameter (triggerMeasType) fordesignating the type of measurement result used to evaluate the eventtriggered criteria. The parameter may be shared with a higher layerparameter for designating the measurement method.

The parameter (reportQuantity) indicating the reporting physicalquantity may be configured as a parameter (reportQuantityRSRP) for theRSRP and a parameter (reportQuantityRSRQ) for the RSRQ for each measuredtype. For example, the reportQuantityRSRP is configured as the firstRSRP and the reportQuantityRSRQ is configured as the second RSRQ, theterminal device 1 transmits the first RSRP and the second RSRQ, and doesnot transmit the second RSRP and the first RSRQ.

As a specific example, the measurement result may be reported dependingon the criteria for designating the measurement.

For example, the type of reported measurement result may be determineddepending on the activated/deactivated state of the target cell.

For example, the type of reported measurement result is determineddepending on the detection of the reference signal. For example, in acase where the CRS is detected and the DRS is not detected, the firstmeasurement result is reported, and if the CRS is not detected and theDRS is detected, the second measurement result is reported. In a casewhere both the CRS and the DRS are detected, the measurement result ofwhich the reception power is higher is reported. In a case where boththe CRS and the DRS are not detected, the measurement result is notreported, or the lowest value is reported.

In order for the base station device 3 to recognize whether the reportedmeasurement result is the result calculated by the first measurement orthe measurement calculated by the second measurement, the terminaldevice 1 may add a parameter indicating the type of measurement to whichthe measurement result is set.

The example of the event triggered criteria and the reporting of themeasurement result has been described. The terminal device 1 reports thefirst measurement result and/or the second measurement result to thebase station device 3 by the combination thereof. In the presentembodiment, the combination of the event, the event triggered criteriaand the reporting of the measurement result is not limited, and anexample of a preferred combination will be described below.

An example of the combination of the event, the event triggered criteriaand the reporting of the measurement result will be described.

In a case where the first measurement is performed, the measurementobject (measObject) including the neighbour cell list or the blacklistfor the physical cell identity is configured is configured, thereporting configuration (reportConfig) for which the event and the eventtriggered criteria triggered by the first measurement are configured isconfigured, and the measurement reporting message including the firstmeasurement result (measResults) is transmitted in association withthese parameters by the ID. In a case where the second measurement isperformed, the measurement object (measObject) including the newneighbour cell list or the new blacklist for which the extended cell IDis configured is configured, the reporting configuration (reportConfig)for which the event and the event triggered criteria triggered by thesecond measurement are configured is configured, and the measurementreporting message including the second measurement result (measResults)is transmitted in association with these parameters by the ID.

That is, the measurement object, reporting configuration and measurementresult for the first measurement and the measurement object, measurementconfiguration and measurement result for the second measurement areconfigured for the terminal device 1. That is, the reportingconfiguration for the first measurement result and the reportingconfiguration for the second measurement result are respectivelyconfigured.

An example of the combination of the event, the event triggered criteriaand the reporting of the measurement result will be described.

In a case where the first measurement is performed, the measurementobject (measObject) including the neighbour cell list or the blacklistfor which the physical cell identity is configured is configured, thereporting configuration (reportConfig) for which the event and the eventtriggered criteria triggered by the first measurement are configured isconfigured, and these parameters are associated with the measurementresults (measResults) by the ID. In a case where the second measurementis performed, the measurement object (measObject) including the newneighbour cell list or the new blacklist for which the extended cell IDis configured is configured, the reporting configuration (reportConfig)for which the event and the event triggered criteria triggered by thesecond measurement are configured is configured, and these parametersare associated with the measurement results (measResults) by the ID. Ina case where the event triggered by the first measurement occurs, thefirst measurement result is substituted for the measurement result, andis transmitted by the measurement reporting message. In a case where theevent triggered by the second measurement occurs, the second measurementresult is substituted for the measurement result, and is transmitted bythe measurement reporting message.

That is, the measurement object and reporting configuration for thefirst measurement and the measurement object and reporting configurationfor the second measurement are configured, and the field of themeasurement result is shared between the first measurement and thesecond measurement. The first measurement result or the secondmeasurement result is transmitted by the event.

Accordingly, the terminal device 1 may report the first measurementresult and the second measurement result to the base station device 3.

The terminal device 1 according to the present embodiment is theterminal device 1 that communicates with the base station device 3, andincludes a reception unit 105 which performs first measurement based ona first RS (CRS), and performs second measurement based on a second RS(DRS), and a higher layer processing unit 101 that reports the firstmeasurement result and the second measurement result to the base stationdevice 3. The terminal device reports the first measurement result tothe base station device 3 in a first state, and reports the firstmeasurement result or the second measurement result to the base stationdevice 3 in a second state.

As an example, in the second state, an event in which the firstmeasurement result is reported an event in which the second measurementresult is reported are configured by the base station device 3. As anexample, in the second state, only the event in which the secondmeasurement is reported is configured by the base station device 3. Anevent triggered criteria in which the second measurement result isreported is defined using the second measurement result.

As an example, the first state is a state in which configurationinformation of the second RS is not notified, and the second state is astate in which configuration information of the second RS is notifiedfrom the base station device 3. As an example, the first state is astate in which the second measurement information is not configured, andthe second state is a state in which the second measurement informationis configured from the base station device 3. As an example, the secondstate is a state in which the first RS is not transmitted.

Reporting configuration for the DRS may be individually set fromreporting configuration for the CRS or CSI-RS.

A value is determined depending on a path loss in transmission power orpower headroom (PHR). Hereinafter, an example of a method of estimatingthe path loss (channel attenuation value) will be described.

A downlink path loss estimation value of a serving cell c is calculatedby the terminal device 1 using the expression ofPLc=referenceSignalPower−higher layer filtered RSRP. Here, thereferenceSignalPower is given in the higher layer. ThereferenceSignalPower is information based on the transmission power ofthe CRS. Here, the higher layer filtered RSRP is a first RSRP of areference serving cell filtered in the higher layer.

In a case where the serving cell c belongs to TAG (pTAG) including theprimary cell, the primary cell is used as the reference serving cell ofthe referenceSignalPower and the higher layer filtered RSRP for theuplink primary cell. The serving cell configured by a parameter ofpathlossReference linking of the higher layer is used as the referenceserving cell of the referenceSignalPower and the higher layer filteredRSRP for the uplink secondary cell. In a case where the serving cell cbelongs to TAG (for example, sTAG) that does not include the primarycell, the serving cell c is used as the reference serving cell of thereferenceSignalPower and the higher layer filtered RSRP.

An example of the method of estimating the path loss will be described.

The downlink path loss estimation value of the serving cell c iscalculated by the terminal device 1 by using the expression ofPLc=discoveryReferenceSignalPower−higher layer filtered RSRP2 in a casewhere the parameter is configured by the higher layer or by using theexpression of PLc=referenceSignalPower−higher layer filtered RSRP in acase where the parameter is not configured by the higher layer. Here,the referenceSignalPower is given in the higher layer. ThereferenceSignalPower is information based on the transmission power ofthe CRS. Here, the higher layer filtered RSRP is a first RSRP of thereference serving cell filtered in the higher layer. Here, thediscoveryReferenceSignalPower is a parameter related to the transmissionpower of the DRS, and is given in the higher layer. The higher layerfiltered RSRP2 is a second RSRP of the reference serving cell filteredin the higher layer.

Here, the case where the parameter is configured by the higher layer maybe, for example, a case where the parameter is based on theconfiguration of the DRS notified using the higher layer signalling. Thecase where the parameter is configured by the higher layer may be, forexample, a case where the parameter is based on the configuration of themeasurement notified using the higher layer signalling. The case wherethe parameter is configured by the higher layer may be, for example, acase where the parameter is based on the configuration of the uplinktransmission power control notified using the higher layer signalling.That is, the case where the parameter is configured by the higher layermay include a case where the parameter or the information is notifiedusing the higher layer signalling and is configured for the terminaldevice 1.

In a case where the serving cell c belongs to the TAG including theprimary cell, the primary cell is used as the reference serving cell ofthe discoveryReferenceSignalPower and the higher layer filtered RSRP2for the uplink primary cell. The serving cell configured by a parameterof pathlossReferenceLinking of the higher layer is used as the referenceserving cell of the discoveryReferenceSignalPower and the higher layerfiltered RSRP2 for the uplink secondary cell. In a case where theserving cell c belongs to the TAG that does not include the primarycell, the serving cell c is used as the reference serving cell of thediscoveryReferenceSignalPower and the higher layer filtered RSRP2.

In a case where the secondary cell is in the deactivated state, theterminal device 1 may not perform the following process. The processincludes the transmission of the SRS in the secondary cell, thereporting of the channel quality indicator (CQI)/precoding matrixindicator (PMI)/rank indicator (RI)/precoding type indicator (PTI) forthe secondary cell, the transmission of the uplink data (UL-SCH) in thesecondary cell, the transmission of the RACH in the secondary cell, themonitoring of the PDCCH in the secondary cell, and the monitoring of thePDCCH for the secondary cell.

In a case where the secondary cell is the small cell, even in a casewhere the secondary cell is in the deactivated state, the terminaldevice 1 may perform the following process. The process includes thetransmission of the SRS in the secondary cell, the reporting of theCQI/PMI/RI/PTI for the secondary cell, (the transmission of the uplinkdata (UL-SCH) in the secondary cell), the transmission of the RACH inthe secondary cell, the monitoring of the PDCCH in the secondary cell,and the monitoring of the PDCCH for the secondary cell.

In a case where the secondary cell in the deactivated state is the smallcell, if there is a request for the SRS transmission to the secondarycell from the primary cell (PDCCH/EPDCCH (DCI format) transmitted in theprimary cell) (a SRS request is transmitted) through cross-carrierscheduling, the terminal device 1 may transmit the SRS in the secondarycell. That is, in this case, the base station device 3 expects toreceive the SRS.

In a case where the secondary cell in the deactivated state is the smallcell, if there is a request for the CSI reporting to the secondary cellfrom the primary cell (PDCCH/EPDCCH (DCI format) transmitted in theprimary cell) (a CSI request is transmitted) through cross-carrierscheduling, the terminal device 1 may transmit the CQI/PMI/RI/PTI forthe secondary cell by using the PUSCH of the primary cell. That is, inthis case, the base station device 3 expects to receive theCQI/PMI/RI/PTI for the secondary cell by using the PUSCH of the primarycell.

In a case where the secondary cell in the deactivated state is the smallcell, if a random access response grant (RAR grant) through a PDCCHorder is transmitted from the primary cell (PDCCH/EPDCCH (DCI format)transmitted in the primary cell) through cross-carrier scheduling, theterminal device 1 may perform the RACH transmission in the secondarycell. That is, in this case, the base station device 3 expects toreceive the RACH in the secondary cell.

In a case where the secondary cell in the deactivated state is the smallcell, if the DCI format accompanying by the CRC scrambled with theRA-RNTI can be detected for the secondary cell from the primary cell(PDCCH/EPDCCH (DCI format) transmitted in the primary cell) throughcross-carrier scheduling, the terminal device 1 may perform the RACHtransmission in the secondary cell. That is, in this case, the basestation device 3 expects to receive the RACH in the secondary cell.

In a case where the secondary cell in the deactivated state is the smallcell, if the configuration (or EPDCCH configuration) of the EPDCCH setis not set to the secondary cell, the terminal device 1 may monitor thePDCCH in the secondary cell. That is, in this case, the base stationdevice 3 may transmit the PDCCH in the small cell in the deactivatedstate.

In a case where the secondary cell in the deactivated state is the smallcell, if the downlink grant or the uplink grant, the CSI request or theSRS request, or the random access response grant are transmitted to thesecondary cell from the primary cell (PDCCH/EPDCCH (DCI format)transmitted in the primary cell) through cross-carrier scheduling, theterminal device 1 may monitor the PDCCH for the secondary cell. In thiscase, only in a case where the EPDCCH set (or EPDCCH configuration) isnot configured for the terminal device 1 or the terminal device 1 doesnot support a function of receiving the DCI by using the EPDCCH, theterminal device 1 may monitor the PDCCH for the secondary cell. That is,in this case, the base station device 3 may transmit the PDCCH in thesmall cell in the deactivated state.

In a case where the secondary cell in the deactivated state is the smallcell, even though information related to the uplink scheduling istransmitted to the secondary cell, the terminal device 1 may not performthe uplink transmission based on the information related to the uplinkscheduling. That is, in this case, the base station device 3 does notexpect that the uplink transmission is performed in the small cell inthe deactivated state.

In a case where the secondary cell in the deactivated state is theprimary secondary cell (special secondary cell), if there is a requestfor the SRS transmission to the secondary cell (a SRS request istransmitted) through self-scheduling, the terminal device 1 may transmitthe SRS in the secondary cell. That is, in this case, the base stationdevice 3 expects to receive the SRS.

In a case where the secondary cell in the deactivated state is theprimary secondary cell, if there is a request for the CSI reporting forthe secondary cell (a CSI request is transmitted) throughself-scheduling, the terminal device 1 may transmit the CQI/PMI/RI/PTIfor the secondary cell by using the PUSCH of the secondary cell.

In a case where the secondary cell in the deactivated state is theprimary secondary cell, if the random access response grant (RAR grant)through the PDCCH order is transmitted through self-scheduling, theterminal device 1 may perform the RACH transmission in the secondarycell.

In a case where the secondary cell in the deactivated state is theprimary secondary cell, if the DCI format accompanying by the CRCscrambled with the RA-RNTI can be detected for the secondary cellthrough self-scheduling, the terminal device 1 may perform the RACHtransmission in the secondary cell.

In a case where the secondary cell in the deactivated state is theprimary secondary cell, if the EPDCCH is not configured for thesecondary cell, the terminal device 1 may monitor the PDCCH in thesecondary cell. That is, if the configuration of the EPDCCH set is notreceived for the primary secondary cell, the terminal device 1 maymonitor the PDCCH in the secondary cell. If the configuration of theEPDCCH set is not set to the primary secondary cell, the base stationdevice 3 may transmit the PDCCH for the terminal device 1 in thesecondary cell.

In a case where the secondary cell in the deactivated state is theprimary secondary cell, if the downlink grant or the uplink grant, theCSI request or the SRS request, or the random access response grant istransmitted for the secondary cell through self-scheduling, the terminaldevice 1 may monitor the PDCCH for the secondary cell. In this case,only in a case where the EPDCCH set is not configured for the terminaldevice 1 or the terminal device 1 does not support a function ofreceiving the DCI by using the EPDCCH, the terminal device 1 may monitorthe PDCCH for the secondary cell.

In a case where the secondary cell in the deactivated state is theprimary secondary cell, if information (PUSCH grant, CSI request or SRSrequest) related to the uplink scheduling is transmitted for thesecondary cell through self-scheduling, the terminal device 1 mayperform the uplink transmission based on the information related to theuplink scheduling in the secondary cell. For example, in a case wherethe DCI format 0 is detected for the secondary cell, the terminal device1 may perform the PUSCH transmission in the secondary cell.

In a case where the secondary cell in the deactivated state is theprimary secondary cell (special secondary cell), if there is a requestfor the SRS transmission to the secondary cell from the primary cell(PDCCH/EPDCCH (DCI format) transmitted in the primary cell) (a SRSrequest is transmitted) through cross-carrier scheduling, the terminaldevice 1 may transmit the SRS in the secondary cell. In this case, theterminal device 1 may support a function of performing the cross-carrierscheduling of the primary cell and the primary secondary cell.

In a case where the secondary cell in the deactivated state is theprimary secondary cell, if there is a request for the CSI reporting forthe secondary cell from the primary cell (PDCCH/EPDCCH (DCI format)transmitted in the primary cell) (a CSI request is transmitted) throughcross-carrier scheduling, the terminal device 1 may transmit theCQI/PMI/RI/PTI for the secondary cell by using the PUSCH of the primarycell. In this case, the terminal device 1 may support a function ofperforming cross-carrier scheduling of the primary cell and the primarysecondary cell.

In a case where the secondary cell in the deactivated state is theprimary secondary cell, if the random access response grant (RAR grant)through a PDCCH order is transmitted from the primary cell (PDCCH/EPDCCH(DCI format) transmitted in the primary cell) through cross-carrierscheduling, the terminal device 1 may perform the RACH transmission inthe secondary cell. In this case, the terminal device 1 may support afunction of performing cross-carrier scheduling of the primary cell andthe primary secondary cell. In this case, the base station device 3 maytransmit the random access response grant (RAR grant) through the PDCCHorder to the secondary cell in the deactivated state throughcross-carrier scheduling.

In a case where the secondary cell in the deactivated state is theprimary secondary cell, if the DCI format accompanying by the CRCscrambled with RA-RNTI can be detected for the secondary cell from theprimary cell (PDCCH/EPDCCH (DCI format) transmitted in the primarycell), the terminal device 1 may perform the RACH transmission in thesecondary cell. In this case, the terminal device 1 may support afunction of performing cross-carrier scheduling of the primary cell andthe primary secondary cell.

In a case where the secondary cell in the deactivated state is theprimary secondary cell, if the EPDCCH set is not configured for thesecondary cell, the terminal device 1 may monitor the PDCCH in thesecondary cell.

In a case where the secondary cell in the deactivated state is theprimary secondary cell, if the downlink grant or the uplink grant, theCSI request or the SRS request, or the random access response grant istransmitted to the secondary cell from the primary cell (PDCCH/EPDCCH(DCI format) transmitted in the primary cell) through cross-carrierscheduling, the terminal device 1 may monitor the PDCCH for thesecondary cell. In this case, only in a case where the EPDCCH set is notconfigured for the terminal device 1 or the terminal device 1 does notsupport a function of receiving the DCI by using the EPDCCH, theterminal device 1 may monitor the PDCCH for the secondary cell.

In a case where the cross-carrier scheduling is invalid for thesecondary cell in the deactivated state, the terminal device 1 maymonitor the PDCCH in the secondary cell in the deactivated state.

In a case where the cross-carrier scheduling is invalid for thesecondary cell in the deactivated state and various configurationsrelated to the EPDCCH are not received, the terminal device 1 maymonitor the PDCCH in the secondary cell in the deactivated state.

If the EPDCCH configuration and/or the configuration of the EPDCCH setare not performed for the secondary cell in the deactivated state, theterminal device 1 may monitor the PDCCH in the secondary cell in thedeactivated state. The base station device 3 may determine whether ornot the PDCCH is transmitted in the secondary cell in the deactivatedstate to the terminal device 1 depending on whether or not the EPDCCHconfiguration and/or the configuration of the EPDCCH set for thesecondary cell in the deactivated state is set.

In a case where the secondary cell in the deactivated state is theprimary secondary cell, if the information related to the uplinkscheduling is transmitted to the secondary cell from the primary cellthrough the cross-carrier scheduling, the terminal device 1 may performthe uplink transmission based on the information related to the uplinkscheduling. In this case, the terminal device 1 may support a functionof performing the cross-carrier scheduling of the primary cell and theprimary secondary cell.

If a certain serving cell is configured such that the terminal device 1receives PDSCH data transmission according to Transmission Modes 1 to 9through the higher layer signalling and is configured such that theterminal device 1 monitors the EPDCCH, the terminal device 1 assumesthat the antenna ports 0 to 3 and 107 to 110 of the serving cell arequasi co-located for the Doppler shift, Doppler spread, average delayand delay spread.

In a case where a certain serving cell is configured such that theterminal device 1 receives the PDSCH data transmission according toTransmission Mode 10 through higher layer signalling and is configuredsuch that the terminal device 1 monitors the EPDCCH for each EPDCCH-PRBset, and if the certain cell is configured by the higher layer such thatthe terminal device 1 decodes the PDSCH according to quasi co-location(QCL) type A, the terminal device 1 assumes that the antenna ports 0 to3 and the antenna ports 107 to 110 of the serving cell are quasico-located for the Doppler shift, Doppler spread, average delay, anddelay spread. Meanwhile, if the certain cell is configured by the higherlayer that the terminal device 1 decodes the PDSCH according to quasico-location type B, the terminal device 1 assumes that the antenna ports15 to 22 and the antenna ports 107 to 110 corresponding to a higherlayer parameter (qcl-CSI-RS-ConfigNZPId) for the Doppler shift, Dopplerspread, average delay, and delay spread.

According to the QCL type A, it may be assumed in the terminal device 1that the antenna ports 0 to 3 and the antenna ports 107 to 110 of theserving cell are quasi co-located for the Doppler shift, Doppler spread,average delay, and delay spread.

According to the QCL type B, it may be assumed in the terminal device 1that the antenna ports 107 to 110 and the antenna ports 15 to 22corresponding to the higher layer parameter (qcl-CSI-RS-ConfigNZPId) arequasi co-located for the Doppler shift, Doppler spread, average delay,and delay spread.

That is, in a case where the type A is set to the terminal device 1based on the higher layer parameter QCL operation, it is assumed thatthe antenna ports 0 to 3 and the antenna ports 107 to 110 of the servingcell are quasi co-located, and in a case where the type B is set, it isassumed that the antenna ports 107 to 110 and the antenna ports 15 to 22corresponding to the higher layer parameter (qcl-CSI-RS-ConfigNZPId) arequasi co-located. In other words, in a case where the type A is set tothe terminal device 1 configured so as to monitor the EPDCCH based onthe higher layer parameter QCL operation, it is assumed that the CRS andthe EPDCCH are quasi co-located, and in a case where the type B is set,it is assumed that the CSI-RS and the EPDCCH are quasi co-located.

In a case where a certain serving cell is configured such that theterminal device 1 receives PDSCH data transmission corresponding toTransmission Mode 10 through the higher layer signalling and eachEPDCCH-PRB set is configured that the terminal device 1 monitors theEPDCCH, a parameter set (PDSCH-RE-MappingQCL-Config) indicated by thehigher layer parameter (re-MappingQCL-ConfigId orPDSCH-RE-MappingQCL-ConfigId) is used in order to determine the quasico-location of the EPDCCH antenna ports and the mapping of the EPDCCHresource elements. In order to determine the mapping of the EPDCCHresource elements and the quasi co-location of the EPDCCH antenna ports,various parameters (crs-PortsCount, crs-FreqShift,mbsfn-SubframeConfigList, csi-RS-ConfigZPId, pdsch-Start, andqcl-CSI-RS-ConfigNZPId) are included in the parameter set.

In a case where a certain serving cell (secondary cell) is configuredsuch that the terminal device 1 receives the DRS through the higherlayer signalling and is configured such that the terminal device 1monitors the EPDCCH, the higher layer parameter (qcl-DRS-ConfigId) fordetermining the mapping of the DRS and EPDCCH resource elements and thequasi co-location of the EPDCCH antenna ports may be configured.

In a case where a certain serving cell (secondary cell) is configuredsuch that the terminal device 1 receives the DRS through the higherlayer signalling and is configured such that the terminal device 1monitors the EPDCCH, the terminal device 1 assumes that the antennaports 107 to 110 and one or more antenna ports corresponding to thehigher layer parameter (qcl-DRS-ConfigId) are quasi co-located.

In order to determine the mapping of the EPDCCH resource elements andthe quasi co-location of the EPDCCH antenna ports with respect to theDRS, various parameters (drs-PortsCount, drs-FreqShift, drs-ConfigZPId,qcl-DRS-ConfigNZPId, and qcl-DRS-ConfigId) may be set. That is, thenumber of DRS antenna ports (drs-PortsCount) may be included in theconfiguration of the quasi co-location of the EPDCCH and the DRS. TheDRS frequency shift (drs-FreqShift) may be included in the configurationof the quasi co-location of the EPDCCH and the DRS. A zero power DRS-ID(drs-ConfigZPId) may be included in the configuration of the quasico-location of the EPDCCH and the DRS. Non-zero power DRS ID(qcl-DRS-ConfigNZPId) that is quasi co-located may be included in theconfiguration of the quasi co-location of the EPDCCH and the DRS.

A signal as a target which is quasi co-located with the EPDCCH may bechanged depending on the activated/deactivated state of the serving cell(secondary cell). For example, the terminal device 1 may assume that theDRS and the EPDCCH are quasi co-located in the deactivated state of theserving cell and may assume that the CRS and the EPDCCH are quasico-located in the activated state of the serving cell. The terminaldevice 1 may assume that the CSI-RS and the EPDCCH are quasi co-locatedin the deactivated state of the serving cell and may assume that the CRSand the EPDCCH are quasi co-located in the activated state of theserving cell. The terminal device 1 may assume that the CSI-RS, the CRS,and the EPDCCH are quasi co-located in the activated state of theserving cell and may assume that the CSI-RS and the EPDCCH are quasico-located in the deactivated state of the serving cell. That is, theterminal device 1 determines that the quasi co-location of the EPDCCH(the mapping of the resource elements and the antenna ports) based onthe set configuration information. In a case where the quasi co-locationof the EPDCCH is changed in the activated state and deactivated state,the base station device 3 may transmit the information related to theplurality of QCL configurations.

Hereinafter, the discontinuous reception (DRX) will be described.

The terminal device 1 may configure the DRX by the RRC accompanying bythe DRX function in order to control the activation (whether or not toperform the PDCCH monitoring) of the PDCCH monitoring of the terminaldevice 1 for the C-RNTI, TPC-PUCCH-RNTI, TPC-PUSCH-RNTI, and SPS-RNTI ofthe terminal device 1. If the DRX is not configured, the terminal device1 continues to successively monitor the PDCCH. In order to perform theDRX, a plurality of timers (onDurationTimer, drx-InactivityTimer, anddrx-RetransmissionTimer) is configured for the terminal device 1. Acycle (longDRX-Cycle or shortDRX-Cycle) and a start offset(drxStartOffset) are configured, and thus, a subframe in which the PDCCHis monitored during the DRX is configured. Parameters(drxShortCycleTimer and shortDRX-Cycle) related to short DRX may beconfigured as options. A HARQ RTT timer is defined for each DL HARQprocess (except for a broadcast process). A period during which thePDCCH can be monitored during the DRX is referred to as an active time.

The active time may be a time during which at least one timer of aplurality of timers (onDurationTimer, drx-InactivityTimer,drx-RetransmissionTimer, and mac-ContentionResolutionTimer) is started.The active timer is a time during which a scheduling request istransmitted through the PUCCH and is pending. The active time may be atimer during which there is an uplink grant for the HARQ transmissionbeing pending and data is present in corresponding HARQ buffer. Theactive time may be a time during which the PDCCH indicating newtransmission related to the C-RNTI of the terminal device 1 is notreceived after the reception of the random access response for apreamble which is not selected by the terminal device 1 succeeds. Theactive time may be the number of subframes configured as a DRX activetime (drx-Activetime).

If the DRX is configured, the terminal device 1 starts a DRXretransmission timer (drx-RetransmissionTimer) of the corresponding HARQprocess for each subframe if the HARQ RTT timer expires in each subframeand the decoding of the data of the corresponding HARQ process does notsucceed.

If the DRX is configured, the terminal device 1 stops the duration timer(onDurationTimer) and the DRX inactivity timer (drx-InactivityTimer) foreach subframe if the DRX command MAC control element (MAC CE) isreceived.

The duration timer (onDurationTimer) is used to define the successivePDCCH subframe at the inception of the DRX cycle.

The DRX inactivity timer (drx-InactivityTimer) is used to define thenumber of successive PDCCH subframes after the subframe in which thePDCCH indicating the transmission of initial uplink/downlink user datato a certain terminal device 1 is transmitted.

The DRX retransmission timer (drx-RetransmissionTimer) is used to definethe maximum number of successive PDCCH subframes until the downlinktransmission is received.

The HARQ RTT timer is used to define the minimum number (minimum amount)of subframes before the downlink HARQ transmission is expected by theterminal device 1.

A MAC contention resolution timer (mac-ContentionResolutionTimer) isused to define the number of successive subframes in which the terminaldevice 1 after Message 3 (PUSCH corresponding to the random accessresponse grant) is transmitted monitors the PDCCH.

A DRX short cycle timer (drxShortCycleTimer) is used to define thenumber of successive subframes in which the terminal device 1 follows ashort DRX cycle.

A DRX start offset (drxStartOffset) is used to define the subframe inwhich the DRX cycle is started.

The active timer defines a time associated to the DRX operation and aperiod (time) during which the terminal device 1 monitors the PDCCH in aPDCCH monitoring subframe.

The PDCCH monitoring subframe is basically the same as the PDCCHsubframe. However, in a case where the terminal device 1 can perform theeIMTA in a certain serving cell, the PDCCH monitoring subframe is thedetermined downlink subframe and a subframe including the DwPTSdepending on the TDD UL-DL configuration indicated by the L1 signalling(for example, the DCI format with which the eIMTA-RNTI is scrambled)related to the eIMTA.

If the DRX is configured, if the DRX inactivity timer expires or the DRXcommand MAC CE is received in each subframe and the short DRX cycle isconfigured, the terminal device 1 starts (restarts) the DRX short cycletimer (drxShortCycleTimer) for each subframe, and uses the DRX cycle.Otherwise, the terminal device uses a log DRX cycle.

If the DRX is configured, if the DRX short cycle timer expires, theterminal device 1 uses the log DRX cycle for each subframe.

If the DRX is configured, in a case where an expression satisfies apredetermined condition based on a system frame number, a subframenumber, a short DRX cycle (and/or log DRX cycle), and a DRX start offset(drxStartOffset), the terminal device 1 starts the duration timer foreach subframe.

If the DRX is configured, if the PDCCH subframe is not necessary in theuplink transmission for half-duplex FDD terminal device operation duringthe active time or this subframe is not a part of a measurement gap forthis subframe is configured, the terminal device 1 monitors the PDCCHfor each subframe. If the PDCCH indicates the downlink transmission orif the downlink assignment is configured for the subframe, the HARQ RTTtimer for the corresponding HARQ process is started, and the DRXretransmission timer for the corresponding HARQ process is stopped. In acase where the PDCCH indicates the new transmission (downlink oruplink), the DRX inactivity timer is started (or restarted).

If the DRX is configured, if the timer is not in the active time inconsideration of the scheduling request transmitted and thegrant/assignment/DRX command MAC CE received until the subframe n−5(including the subframe n−5) in which all the DRX active time conditionsare evaluated by the terminal device 1 in the latest subframe n, theterminal device 1 does not transmit a trigger type 0 SRS to eachsubframe.

If the DRX is configured, if CQI masking (cqi-Mask) is set up by thehigher layer, the terminal device 1 does not report the CQI/PMI/RI/PTIin the PUCCH for each subframe if the duration timer is not in theactive time in consideration of the grant/assignment/DRX command MAC CEreceived until the subframe n−5 (including the subframe n−5) in whichall the DRX active time conditions are evaluated in the latest subframen. Otherwise, if the terminal device 1 is not in the active time inconsideration of the grant/assignment/DRX command MAC CE received untilthe subframe n−5 (including the subframe n−5) in which all the DRXactive time conditions are evaluated in the latest subframe n, theCQI/PMI/RI/PTI (that is, CSI) is not reported in the PUCCH.

If there is an occurrence possibility irrespective of whether or not theterminal device 1 monitors the PDCCH, the terminal device 1 mayreceive/transmit the HARQ feedback, and may transmit the trigger type 1SRS.

The same active time may be applied to all activated serving cells.

In the case of the spatial multiplexing of the downlink, if thetransport block is received during which the HARQ RTT timer is beingstarted and during which the transmission before the same transportblock is received in a subframe which is positioned before at least Nsubframes from the latest subframe, the terminal device 1 may processthe transport block, and may restart the HARQ RTT timer. Here, Nequivalent to a value set to the HARQ RTT timer or the HARQ RTT timer.

In a case where the DRX is configured in the primary cell and theconfiguration of the DRS for the secondary cell is set, and in a casewhere the measurement subframe set based on the configuration of the DRSand the PDCCH subframe set based on the configuration of the DRXoverlap, the terminal device 1 may perform the DRS measurement and thePDCCH monitoring in the secondary cell in the deactivated state in theoverlapped subframe. The DRX active timer is applied to the activationserving cell, that is, all the serving cell in the activated state, butis not applied to the deactivation serving cell, that is, the servingcells in the deactivated state. In a case where the DRS configuration isset, the DRX active timer may be applied in the serving cell (orsecondary cell) even in the deactivation state (off state, deactivation,or dormant mode). In this case, the DRS configuration may not includethe subframe configuration. That is, the base station device 3 maytransmit the DRS based on the DRX active time.

In a case where the DRX is configured in all the activation servingcells, the terminal device 1 may measure the DRS in the subframe ofwhich the timer becomes the active time by the DRX in the small cell inthe deactivated state to which the configuration of the DRS is set.

In a case where the DRX deactivation timer or the duration timerexpires, the terminal device 1 may not perform the measurement of theDRS even though the expired subframe can be measured based on the DRSmeasurement subframe. That is, in a case where the DRX deactivationtimer or the duration timer expires, the terminal device 1 does notexpect that the DRS is transmitted in the subsequent DRS measurementsubframes.

In a case where the DRS configuration for the secondary cell in thedeactivated state (as the small cell) is notified (provided or given)using the higher layer signalling in the terminal device 1 for which theDRX is configured, the terminal device 1 may perform the RPM(RSRP/RSRQ/RSSI) measurement of the DRS in the DRS transmission subframeof the secondary cell overlapping with the active time of the DRX.

The configuration of the DRX (drx-Config) may be individually set to theMCG and the SCG, or the primary cell and the primary secondary cell, orthe MeNB and the SeNB. The DRX in the SCG may indicate theactivated/deactivated state of the primary secondary cell. In a casewhere the DRX is configured for the SCG, the DRS and the PDCCH may betransmitted in the DRX subframe.

Here, although the configuration of the DRX has been performed, variousparameters set to the configuration of the DRX may be set as theconfiguration of discontinuous transmission (DTX).

Hereinafter, radio link monitoring will be described. The radio linkmonitoring means that the downlink radio link quality of the primarycell is monitored by the terminal device 1 in order to indicate to thehigher layer that the radio link quality is in-sync or out-of-sync.

In the non-DRX operation, the physical layer of the terminal device 1evaluates the radio link quality evaluated over the past (previous) timeperiod using thresholds (Q_(in) and Q_(out)) defined based on the testassociated with the radio link monitoring for each radio frame (thenumber of subframes constituting the radio frame)

In the DRX operation, the physical layer of the terminal device 1evaluates the radio link quality evaluated over the past (previous) timeperiod using thresholds (Q_(in) and Q_(out)) defined based on the testassociated with the radio link monitoring for each at least one DRX (thenumber of subframes constituting the DRX cycle).

If the higher layer signalling indicates a certain subframe in order tolimit the radio link monitoring, the radio link quality is not monitoredin the subframe other than the subframe indicated by the higher layersignalling. That is, in a case where the subframe in which the radiolink monitoring is performed is limited by the higher layer signalling,the terminal device 1 performs the radio link monitoring only in thelimited subframe.

In a case where the radio link quality is worse than the thresholdQ_(out) in the radio frame in which the radio link quality is evaluated,the physical layer of the terminal device 1 indicates to the higherlayer that the radio link quality is the out-of-sync. In a case wherethe radio link quality is better than the threshold Q_(in), the physicallayer of the terminal device 1 indicates to the higher layer that theradio link quality is the in-sync in the radio frame in which the radiolink quality is evaluated.

The physical layer of the terminal device 1 that supports the dualconnectivity may perform the radio link monitoring on the primary celland the primary secondary cell. The thresholds related to the radio linkquality may be defined for the primary cell and the primary secondarycell.

The physical layer of the terminal device 1 that supports the dualconnectivity may individually evaluate the radio link quality(out-of-sync or in-sync) on the primary cell and the primary secondarycell.

When the radio link quality is evaluated, in a case where theout-of-sync is continued a predetermined number of times, the physicallayer of the terminal device 1 that supports the dual connectivitystarts a protection timer. In a case where the protection timer expires,the physical layer of the terminal device 1 notifies the higher layerthat the out-of-sync occurs in this cell (in other words, a physicallayer problem is detected). The higher layer of the terminal device 1recognizes that a radio link failure (RLF) is detected in a case wherethe cell in which the physical layer problem is detected is the primarycell. In this case, the higher layer of the terminal device 1 may notifythe base station device 3 that the RLF is detected in the primary cell.The higher layer of the terminal device 1 may not recognize the RLF in acase where the cell in which the physical layer problem is detected isthe primary secondary cell. The higher layer of the terminal device 1may perform the same process as that of the primary cell in a case wherethe cell in which the physical layer problem is detected is the primarysecondary cell.

Hereinafter, the semi-persistent scheduling (SPS) will be described. Ina case where the semi-persistent scheduling is configured to be valid bythe RRC layer (higher layer signalling, or the higher layer), theterminal device 1 receives the following information. This informationincludes the uplink semi-persistent scheduling interval(semiPersistSchedIntervalUL) and the number of times blank transmissionis performed before being implicitly released (implicitReleaseAfter) ina case where the semi-persistent scheduling C-RNTI and thesemi-persistent scheduling are effective for the uplink, and thedownlink semi-persistent scheduling interval(semiPersistSchedIntervalDL) and the number of HARQ processes(numberOfConfSPS-Processes) configured for the semi-persistentscheduling in a case where two parameter configurations(twoIntervalsConfig) are effective for the uplink or the semi-persistentscheduling is effective for the downlink only in the TDD.

In a case where the semi-persistent scheduling for the uplink ordownlink is configured to be invalid by the RRC layer (higher layersignalling or the higher layer), the corresponding configured grant orconfigured assignment is ignored.

The semi-persistent scheduling is supported only by the primary cell.

The semi-persistent scheduling is not supported for RN communication ofthe E-UTRAN of the connection accompanying by the RN subframeconfiguration.

After the semi-persistent downlink assignment is configured, if N-thassignment occurs in the subframe and system frame number that satisfiesa certain condition, the terminal device 1 regards these frames to becontinued. Here, the certain condition may be determined based on thesystem number (SFN_(start) _(_) _(time)) and the subframe(subframe_(start) _(_) _(time)) when the downlink assignment configuredfor the terminal device 1 is initialized (or reinitialized).

After the semi-persistent uplink grant is configured, the terminaldevice 1 sets a subframe offset (Subframe Offset) based on a certaintable if two interval configurations are configured to be valid in thehigher layer, and sets the subframe offset to be 0 if not.

After the semi-persistent uplink grant is configured, if the N-th grantoccurs in the subframe and the system number that satisfies a certaincondition, the terminal device 1 regards these frames to be continued.Here, the certain condition may be determined based on the system framenumber (SFN_(start) _(_) _(time)) and the subframe (subframe_(start)_(_) _(time)) when the uplink grant configured for the terminal device 1is initialized (or reinitialized).

The terminal device 1 clears the configured uplink grant immediatelyafter the number of times blank transmission is performed beforesuccessive MAC protocol data units (PDUs) including a zero MAC servicedata unit (SDU) are implicitly released is given by multiplexing andconstructing entities.

In a case where the terminal device 1 supports a function of performingthe dual connectivity, the SPS may be performed in the primary secondarycell in addition to the primary cell. That is, the SPS configuration maybe set to the primary secondary cell in addition to the primary cell.

In the terminal device 1 that supports the function of performing thedual connectivity, in a case where only one SPS configuration is set,the SPS may be applied to only the primary cell.

In the terminal device 1 that supports the function of performing thedual connectivity, in a case where only one SPS configuration is set,the same configuration may be applied to the primary cell and theprimary secondary cell.

In the terminal device 1 that supports the function of performing thedual connectivity, the downlink SPS configuration and/or the uplink SPSconfiguration may be individually set to the primary cell and theprimary secondary cell. That is, the downlink SPS configuration and/orthe uplink SPS configuration may be common to or may be individuallyconfigured for the primary cell and the primary secondary cell. Whetheror not the SPS is individually performed in the primary cell and theprimary secondary cell in the downlink and/or the uplink may bedetermined based on function information transmitted from the terminaldevice 1.

Hereinafter, the PDCCH and the EPDCCH transmitted in the primarysecondary cell will be described.

The PDCCH transmitted in the primary secondary cell may be scrambledusing the parameter common to the plurality of terminal devices and/orthe previously defined parameter. In a case where the parameter commonto the plurality of terminal devices is not configured, the PDCCH isscrambled using the physical cell identity.

The PDCCH transmitted in the primary secondary cell may becyclic-shifted on a per REG basis based on the parameter common to theplurality of terminal devices and/or the previously defined parameter.In a case where the parameter common to the plurality of terminaldevices is not configured, the PDCCH is cyclic-shifted based on a valueof the physical cell identity.

The USS and the search space different from the USS are allocated to theprimary secondary cell. The search space different from the USS is asearch space which monitors a region common to the plurality of terminaldevices. The CSS allocated to the primary cell is referred to as a firstCSS, and the search space different from the USS allocated to theprimary secondary cell is referred to as a second CSS.

The second CSS is a search space configured using the parameter commonto the plurality of terminal devices and/or the previously definedparameter. The parameter common to the plurality of terminal device isnotified from the higher layer. As an example of the parameter common tothe plurality of terminal devices, the parameter specific to the basestation device 3 (cell or transmission point) is used. For example, asthe parameter specific to the transmission point, the virtual cell ID orTPID is used. As an example of the parameter common to the plurality ofterminal devices, a parameter capable of being individually configuredfor the terminal device, or a parameter for which a value common to theplurality of terminals is configured is used. For example, as theparameter for which the value common to the plurality of terminaldevices is configured, the RNTI is used.

The PDCCH may be allocated to the second CSS. In this case, in thesecond CSS, the CCE in which the search space is started is determinedby using the parameter common to the plurality of terminals and/or thepreviously defined parameter. Specifically, the RNTI (for example,UE-group-RNTI or CSS-RNTI) common to the plurality of terminals isconfigured as an initial value of Y_(k) used in the expression (1) ofFIG. 14. The CCE in which the search space of the second CSS is startedmay be designated in common to the terminals by the higher layerparameter. Specifically, the Y_(k) used in the expression (1) of FIG. 14is constantly a fixed value, and the higher layer parameter (forexample, the parameter for designating the CCE index) is set. Zero maybe constantly set to the Y_(k).

The aggregation levels 4 and 8 of the second CSS allocated to the PDCCHare supported. Four PDCCH candidates are defined in the aggregationlevel 4, and two PDCCH candidates are defined in the aggregation level8. The aggregation levels 1, 2, 16 and 32 may be supported. In thiscase, the number of times blind decoding is performed is not increasedin the second CSS by limiting the number of PDCCH candidates. Forexample, in a case where the aggregation levels 2, 4 and 8 of the secondCSS are supported, two PDCCH candidates are defined in each aggregationlevel.

The EPDCCH may be allocated to the second CSS. In this case, in thesecond CSS, the ECCE in which the search space is started is determinedusing the parameter common to the plurality of terminals and/or thepreviously defined parameter. Specifically, the RNTI (for example,UE-group-RNTI or CSS-RNTI) common to the plurality of terminals isconfigured for an initial value of Y_(p,k) used in the expression (2) ofFIG. 14. The ECCE in which the search space of the second CSS is startedmay be designated in common to the terminals by the higher layerparameter. Specifically, the Y_(p,k) used in the expression (2) of FIG.14 is constantly a fixed value, and the higher layer parameter (forexample, the parameter for designating the ECCE index) is set. Zero maybe constantly set to the Y_(p,k).

In a case where the EPDCCH is allocated to the second CSS, the EPDCCHset allocated to the second CSS may be configured. For example, theEPDCCH set 0 may be allocated to the USS, and the EPDCCH set 1 may beallocated to the second CSS. The USS and the second CSS may be allocatedwithin one EPDCCH set. For example, the EPDCCH set 0 may be allocated tothe USS and the second CSS.

The aggregation levels 4 and 8 of the second CSS to which the EPDCCH isallocated are supported. Four EPDCCH candidates are defined in theaggregation level 4, and two EPDCCH candidates are defined in theaggregation level 8. The aggregation levels 1, 2, 16 and 32 may besupported. In this case, the number of times blind decoding is performedis not increased in the second CSS by limiting the number of PDCCHcandidates. For example, in a case where the aggregation levels 2, 4 and8 of the second CSS are supported, two PDCCH candidates are defined ineach aggregation level.

The second CSS is allocated to the primary secondary cell configuredthrough the dedicated RRC signaling. Thus, it is not necessary toallocate control information associated with the broadcast informationto the second CSS. Thus, it is not necessary to monitor the PDCCH byusing the RNTI related to the information. The type (second RNTI group)of RNTI used in the PDCCH monitoring in the second CSS is different fromthe type (first RNTI group) of RNTI used in the PDCCH monitoring in thefirst CSS.

An example of the type (first RNTI group) of RNTI used in the PDCCHmonitoring in the first CSS will be described.

The terminal device 1 monitors the PDCCH allocated to the first CSS byusing C-RNTI, SPS C-RNTI, SI-RNTI, P-RNTI, RA-RNTI, TPC-PUCCH-RNTI,TPC-PUSCH-RNTI, temporal C-RNTI, M-RNTI, or TDD-ModeA-RNTI.

An example of the type (second RNTI group) of RNTI used in the PDCCHmonitoring in the second CSS will be described.

The PDCCH for notifying of at least random access response, the PDCCHfor indicating the TPC command to a specific terminal device 1, or thePDCCH for notifying of the TDD UL/DL configuration may be allocated tothe second CSS. In a case where backhaul delay between the MeNB and SeNBis large, it is necessary to perform the transmission from the SeNB evenat the time of the RRC reconfiguration. That is, the terminal device 1monitors the PDCCH allocated to the second CSS by using the RA-RNTI,TPC-PUCCH-RNTI, TPC-PUSCH-RNTI, TDD-ModeA-RNTI, C-RNTI, SPS C-RNTI, andtemporary C-RNTI.

Meanwhile, it is not necessary to arrange the PDCCH to which informationrelated to paging is assigned in the second CSS. Since the primarysecondary cell is used in the RRC connected mode, it is not necessary toarrange the PDCCH to which the downlink/uplink grant for transmission bya subordinate transmission scheme required at the time of the RRCreconfiguration is assigned. That is, the terminal device 1 may notmonitor the PDCCH allocated to the second CSS by using the SI-RNTI orthe P-RNTI.

An example of the type (second RNTI group) of RNTI used in the PDCCHmonitoring in the second CSS will be described.

The PDCCH for notifying of at least random access response, the PDCCHfor indicating the TPC command to a specific terminal device 1, or thePDCCH for notifying of the TDD UL/DL configuration may be allocated tothe second CSS. That is, the terminal device 1 monitors the PDCCHallocated to the second CSS by using at least RA-RNTI, TPC-PUCCH-RNTI,TPC-PUSCH-RNTI, and TDD-ModeA-RNTI.

Meanwhile, it is not necessary to arrange the PDCCH to which the systeminformation or information related to paging is assigned in the secondCSS. Since the primary secondary cell is used in the RRC connected mode,it is not necessary to arrange the PDCCH to which the downlink/uplinkgrant for transmission by a subordinate transmission scheme required atthe time of RRC reconfiguration is assigned. That is, the terminaldevice 1 may not monitor the PDCCH allocated to the second CSS by usingthe SI-RNTI, P-RNTI, C-RNTI, SPS C-RNTI or temporary C-RNTI.

The PDCCH including the information indicating the activated/deactivatedstate of the cell may be allocated to the second CSS. That is, theterminal device 1 monitors the PDCCH allocated to the second CSS byusing the RNTI (SCE-RNTI) associated with the small cell ON/OFF.

The terminal device 1 increases the number of times the blind decodingis performed in the primary secondary cell by the second CSS.Specifically, only the USS is allocated to the secondary cell, and boththe USS and the second CSS are allocated to the primary secondary cell.If the number of times the blind decoding is performed in the second CSSis the same as the number of times the blind decoding is performed inthe first CSS, the number of times the blind decoding is performed isincreased to twelve, and the load of the terminal device 1 is increased.

An example in which the number of times blind decoding is performed inthe second CSS is reduced will be described.

In a case where the PDCCH allocated to the second CSS is not monitoredusing the C-RNTI, SPS C-RNTI or Temporary C-RNTI, the DCI format 0/1A isnot allocated to the second CSS, and thus, it is possible to reduce thenumber of times the blind decoding is performed in the second CSS.

In this case, the DCI format 3/3A is padded so as to be adjusted for apayload size of the DCI format 1C. Alternatively, a new DCI format (DCIformat 3B) in which the TPC command is transmitted is configured.

The DCI format 3B is used to transmit the TPC command for the PUCCH andPUSCH through 1-bit power adjustment. The terminal device 1 can detectthe value of the transmission power control command corresponding to thePUSCH or PUCCH by detecting bit information corresponding to the index(TPC-index) assigned to the terminal device. It is determined whetherthe DCI format 3B indicates the transmission power control command forthe PUSCH or the transmission power control command for the PUCCHdepending on the type of the RNTI to be scrambled. The DCI format 3B ispadded so as to be adjusted for a payload size of the DCI format 1C.

Accordingly, since only control information having the same payload sizeas that of the DCI format 1C is allocated to the second CSS, it ispossible to reduce the number of times the blind decoding is performed.Specifically, in the second CSS, the decoding of six PDCCH candidatesand the DCI format having one type of bit size is tried in theaggregation 4, or the decoding of two PDCCH candidates and the DCIformat having one type of bit size is tried in the aggregation 8. Thatis, the terminal device 1 tries to decode in the second CSS six times.Accordingly, it is possible to halve the number of times the blinddecoding is performed in the CSS.

An example in which the number of times the blind decoding is performedin the second CSS is reduced will be described.

In the second CSS, the parity bit is inserted until the payload size ofthe DCI format 1C becomes the same as that of the DCI format 0.Accordingly, since only the control information having the same payloadsize as that of the DCI format 0 is allocated to the second CSS, it ispossible to reduce the number of times the blind decoding is performed.Specifically, in the second CSS, the decoding of 6 PDCCH candidates andthe DCI format having one type of bit size is tried in the aggregation4, and the decoding of 2 PDCCH candidates and the DCI format having onetype of bit size is tried in the aggregation 8. That is, the terminaldevice 1 tries to decode in the second CSS six times. Accordingly, it ispossible to halve the number of times the blind decoding is performed inthe CSS.

All the terminal devices 1 do not support the monitoring of the secondCSS in terms of the increase in the number of times the blind decodingis performed. Thus, information (capability) indicating ability ofwhether or not the terminal device 1 can monitor the second CSS may benotified to the base station device 3.

The terminal device 1 having high processing capability notifies thebase station device 3 of information indicating that the terminal devicecan monitor the second CSS. Meanwhile, the terminal device 1 having lowprocessing capability notifies the base station device 3 of informationindicating that the terminal device is not able to monitor the secondCSS. The base station device 3 acquires the information indicating theability of whether or not the terminal device can monitor the second CSSfrom each terminal device 1, and performs the configuration of thesecond CSS for only the terminal device 1 capable of monitoring thesecond CSS. Here, the base station device 3 may configure the terminaldevice 1 capable of monitoring the second CSS as the UE group.

The base station device 3 arranges the PDCCH in the second CSS, andperforms the notification of the random access response or thenotification of the TDD UL/DL configuration to the terminal device 1capable of monitoring the second CSS.

The base station device 3 arranges the PDCCH in the USS, and performsthe notification of the random access response or the notification ofthe TDD UL/DL configuration to the terminal device 1 which is notcapable of monitoring the second CSS. In this case, in terms of thenumber of times the blind decoding is performed, the DCI format 1A isused in the notification of the random access response, and the DCIformat 1C used in the notification of the TDD UL/DL configuration is fedback until the payload size of the DCI format 1C becomes the same asthat of the DCI format 0.

Accordingly, the notification of the random access response or thenotification of the TDD UL/DL configuration may also be performed to theterminal device 1 having low processing capability, which is not able tomonitor the second CSS.

The information indicating the ability of whether or not the terminaldevice is not able to monitor the second CSS may be notified inassociation with information indicating that the terminal device can beoperated in the dual connectivity mode. That is, if the terminal devicecan be operated in the dual connectivity mode, the terminal device maymonitor the second CSS.

The processes of the terminal device 1 and the base station device 3 ina case where the information indicating the activated/deactivated stateof the secondary cell as the small cell is transmitted using the DCIformat (PDCCH/EPDCCH accompanying by the DCI format) will be described.

One bit indicating the activated/deactivated state of each of theplurality of cells (small cell, secondary cell, and serving cell) may beset to a certain DCI format. For example, a case where the DCI formatincluding the information indicating the activated/deactivated state isconstituted by 15 bits may mean that as much information indicating theactivated/deactivated state as 15 cells is included. That is, theactivated/deactivated state is represented by one bit. The activatedstate being represented by one bit may be simultaneously recognized asthe CSI request for the cell corresponding to one bit. When theactivated state is represented by one bit, the CSI corresponding to onebit is transmitted in the first uplink subframe after a predeterminedsubframe after the CSI is received. Positions of the bits constitutingthe DCI format and a cell index (for example, serving cell index, smallcell index, or ON/OFF cell index) may be previously correlated.

The DCI format may indicate only the activated state. For example, “1”in one bit indicates activation, and “0” indicates that the currentstate is the same as the previous state. In this case, it is preferablethat another method of indicating the deactivated state such as thedeactivation timer is also used.

The DCI format may indicate only the deactivated state. For example, “1”in one bit indicates deactivation, and “0” indicates that the currentstate is the same as the previous state. In this case, it is preferablethat another method of indicating the activated state such as activationnotification through the MAC CE is also used.

n bits indicating the activated/deactivated state of each of theplurality of cells (small cell, secondary cell, and serving cell) may beset to a certain DCI format. For example, a case where the DCI formatincluding the information indicating the activated/deactivated state isconstituted by 15 bits may mean that as much information indicating theactivated/deactivated state as (15/n) cell is included. That is, theactivated/deactivated state may be represented by n bits. For example,information notified in n bits is information of theactivated/deactivated states of the cells of n subframes. Each bit of nbits corresponds to the subframe. Specifically, information notified in8 bits is information indicating the activated/deactivated states of 8subframes. For example, the information notified in n bits isinformation indicating subframe patterns in the activated/deactivatedstate. The subframe pattern in the activated/deactivated state may bepreviously determined. The subframe pattern in the activated/deactivatedstate may be notified in the higher layer. Specifically, informationnotified in 2 bits indicates four subframe patterns. A length of the bitindicating the activated/deactivated state is determined depending onthe maximum number of the types of subframe patterns. The maximum numberof the types of subframe patterns may be configured in the higher layer.

The PDCCH/EPDCCH including the information indicating theactivated/deactivated state is scrambled by the RNTI (for example,SCE-RNTI) for indicating the activated/deactivated state. In a casewhere the decoding of a certain PDCCH/EPDCCH by the SCE-RNTI succeeds,the terminal device 1 recognizes that the information indicating theactivated/deactivated state is included in the PDCCH/EPDCCH.Accordingly, even though the information indicating theactivated/deactivated state is included in the same DCI format as thatof another control information, the terminal device 1 can recognize thatthe information for indicating the activated/deactivated state isincluded.

The information indicating the activated/deactivated state of thesecondary cell as the small cell may be combined with the DCI includinganother information scrambled with another RNTI. For example, thedeactivated state of the cell may be indicated using the state of UL/DLconfiguration 7 in the dynamic TDD. In other words, UL/DL configurations1 to 6 may indicate the activated state of the cell. For example, theactivated/deactivated state of the cell may be indicated using extrabits other than the information indicating the UL/DL configuration inthe dynamic TDD. For example, the activated/deactivated state of thecell may be indicated using the extra bits other than the informationfor notifying of the TPC command.

A field may be configured for the DCI format indicating the downlinkgrant/uplink grant, and information indicating the activated state ofthe secondary cell may be notified. For example, a 3-bit fieldindicating the serving cell is configured for the DCI format 4 or theDCI format 2D. The terminal device 1 recognizes that the serving cellindicated by the DCI format of the downlink grant/uplink grant is in theactivated state.

The field may be configured for the DCI format indicating the downlinkgrant/uplink grant, and information indicating the deactivated state ofthe secondary cell may be notified. For example, a 3-bit fieldindicating the serving cell is configured for the DCI format 4 or theDCI format 2D. The terminal device 1 recognizes that the serving cellindicated by the DCI format of the downlink grant/uplink grant is in thedeactivated state.

It is preferable that the activated/deactivated state is not indicatedby the DCI format including the information indicating theactivated/deactivated state over the plurality of cell groups. Forexample, the information indicating the activated/deactivated statecorresponding to the secondary cell belonging to the master cell groupand the information indicating the activated/deactivated statecorresponding to the secondary cell belonging to the secondary cellgroup are not included in one DCI format. In other words, theinformation indicating the activated/deactivated state included in oneDCI format corresponds to only the serving cell belonging to one cellgroup.

The DCI format including the information indicating theactivated/deactivated state of the cell belonging to the master cellgroup is allocated to the first CSS of the primary cell. In terms of theprocessing load of the blind decoding, it is preferable that the DCIformat including the information indicating the activated/deactivatedstate has the same number of bits as that of another DCI formatallocated to the first CSS. Specifically, the bits of the DCI formatincluding the information indicating the activated/deactivated state arepadded such that the payload size of this DCI format becomes the same asthat of the DCI format 0/1A/3/3A or the DCI format 1C, and this DCIformat is allocated to the first CSS. The terminal device 1 monitors theCSS of the primary cell, and acquires the activated/deactivated statesof the plurality of secondary cells (small cells) of the cell group towhich the primary cell belongs by using the DCI format. Accordingly, itis easy to notify the plurality of terminal devices by using one PDCCH,and thus, overhead is reduced.

The DCI format including the information indicating theactivated/deactivated state of the cell belonging to the secondary cellgroup is allocated to the SS of the primary secondary cell. It ispreferable that the DCI format including the information indicating theactivated/deactivated state of the cell belonging to the secondary cellgroup is allocated to the SS capable of being monitored by the pluralityof terminal devices as the primary secondary cells. For example, the DCIformat including the information indicating the activated/deactivatedstate of the cell belonging to the secondary cell group is allocated tothe second CSS. In terms of the processing load of the blind decoding,it is preferable that the DCI format including the informationindicating the activated/deactivated state has the same number of bitsas that of another DCI format allocated to the second CSS. Specifically,the bits of the DCI format including the information indicating theactivated/deactivated state are padded such that the payload size ofthis DCI format becomes the same as that of the DCI format 0/1A/3/3A orthe DCI format 1C, and this DCI format is allocated to the CSS. Theterminal device 1 monitors the second CSS of the primary secondary cell,and acquires the activated/deactivated states of the plurality ofsecondary cells (small cells) of the cell group to which the primarysecondary cell belongs to by using the DCI format. Accordingly, it iseasy to notify the plurality of terminal devices by using onePDCCH/EPDCCH, and thus, overhead is reduced.

The DCI format including the information indicating theactivated/deactivated state of the cell may be allocated to the USS inthe cell. In this case, the notification may be performed using 1-bitinformation indicating the activated/deactivated state.

The terminal device 1 may continue to recognize theactivated/deactivated state indicated by the transmitted DCI formatuntil the activated/deactivated state is indicated by the next DCIformat indicating the activated/deactivated state of the cell. In thiscase, t is preferable that the DCI format indicating theactivated/deactivated state of the cell is periodically transmitted. Thecycle and timing (subframe) in which the DCI format indicating theactivated/deactivated state is transmitted is notified to the terminaldevice 1. The cycle in which the DCI format indicating theactivated/deactivated state is transmitted is for example, one radioframe (10 subframes) or one half frame (5 subframes). The timing inwhich the DCI format indicating the activated/deactivated state istransmitted is, for example, the subframe 0 or the subframe 5. Theterminal device 1 can explicitly recognize the period during which theactivated/deactivated state is recognized by periodically transmittingthe DCI format.

The terminal device 1 may change the state such that the state isrecognized as the deactivated state before the activated/deactivatedstate is indicated by the next DCI format indicating theactivated/deactivated state of the cell. In this case, for example, atimer (small cell deactivation timer) for performing transition to thedeactivated state is set, and the terminal device 1 recognizes the stateas the deactivated state before the indication from the base stationdevice 3 is received in a case where the timer exceeds.

The activated/deactivated state of each cell (neighbour cell ortransmission point) having a transmission point different that of theserving cell may be indicated by the DCI format. In this case, it ispreferable that the cell having a transmission point different from thatof the serving cell is connected through low-delay backhaul such as anoptical cable.

The ON/OFF cell PDCCH configuration is used to define the RNTI and indexfor indicating the activated/deactivated state of the small cell (or thesecondary cell/serving cell equivalent to the small cell). The ON/OFFfunction of the small cell together with this configuration may be setup or released.

The ON/OFF cell PDCCH configuration may include the RNTI (for example,SCE-RNTI) indicating that the DCI format is the DCI format indicatingthe activated/deactivated state of the small cell (serving cell). TheON/OFF cell PDCCH configuration may include the list of the index of thesmall cell of which the activated/deactivated state is indicated by theDCI format. The activated/deactivated state may be notified to aspecific small cell by this list. For example, in a case where a certainDCI format is constituted by 15 bits, the terminal device 1 may checkthe activated/deactivated state of only the bit corresponding to theindex indicated by the list without checking the activated/deactivatedstates for all the bits. The terminal device may recognize that otherbits are all in the deactivated state.

In a case where the DCI format including the information indicating theactivated state of a certain cell is detected in a certain subframe(i=0, 1, 2, . . . ), the terminal device 1 recognizes that this cell isin the activated state in a subframe i+k (k is a predetermined value).The same process may be performed in the deactivated state. The value ofk may be different between the activated state and the deactivatedstate.

In a case where the information indicating the activated/deactivatedstate is included in the first DCI format, the size of the first DCIformat may be the same as the size of another DCI format. The sizes ofthe DCI formats are equal, and thus, new indication information can beconfigured without increasing the number of times the blind decoding isperformed. In a case where the number (type) of transmitted controlinformation items or the number of required bits are different betweenthe first DCI format and the second DCI format, the bits that are notused as the control information may be padded.

In a case where the information indicating the activated/deactivatedstate us included in the first DCI format, bits other than the bitsrequired for the information indicating the activated/deactivated statemay be removed. That is, the size of the first DCI format may beincreased or decreased if necessary.

In a case where the activated state is indicated by the informationindicating the activated/deactivated state, the terminal device 1 mayperform the CSI measurement on the cell of which the activated state isindicated, and may perform the CSI report in the first uplink subframeafter a predetermined subframe.

In a case where the PDCCH/EPDCCH and the DRS are transmitted in the samesubframe, the URS (or DMRS) may be transmitted in the same subframe inorder to demodulate and decode the PDCCH/EPDCCH.

In a case where the PDCCH/EPDCCH and the DRS are transmitted in the samesubframe, the terminal device 1 may demodulate and decode thePDCCH/EPDCCH by using the DRS (one of the plurality of signalsconstituting the DRS).

In a case where the configuration of the DRS is set to a certain cellthrough the higher layer signalling, if the measurement result does notsatisfy a threshold in the measurement subframe of the DRS on a certaincell a predetermined number of times, the terminal device 1 may requestthe reconfiguration of the DRS by using the primary cell.

Hereinafter, the implicit OFF state (implicit deactivation) of theON/OFF cell will be described.

The ON/OFF cell may be the same as the small cell.

In a case where the inter-cell interference is suppressed by performingthe transition of the base station device 3 from the ON state (operatingstate or activated state) to the OFF state (deactivated state) (referredto as a case where the base station device 3 uses the ON/OFF cell forthe sake of convenience in the description), it is assumed that theON/OFF cell is in the OFF state before the OFF state timer associatedwith the ON/OFF state configured for the terminal device 1 expires.

The OFF state of the ON/OFF cell may be a state in which the terminaldevice 1 does not expect the downlink transmission from the base stationdevice 3. That is, the OFF state may be a state in which at least one ofthe PSS/SSS, the CRS, the CSI-RS, the PBCH, the PDCCH, the EPDCCH, andthe PDSCH is not transmitted. For example, the OFF state may be a statein which the PSS/SSS is not transmitted over one or more half frame (5or more subframes). For example, the OFF state of the base stationdevice 3 is a state in which only the DRS is transmitted.

The OFF state of the ON/OFF cell may be a state in which the terminaldevice 1 performs a process different from that in the terminal deviceof the related art, and the ON state of the ON/OFF cell may be a statein which the terminal device 1 can perform the same process as that inthe terminal device of the related art.

In the OFF state of the ON/OFF cell, the terminal device 1 may performthe uplink transmission of the PUCCH or the PUSCH in the ON/OFF cell.That is, the ON/OFF cell may also perform the reception process in theOFF state.

In the OFF state of the ON/OFF cell, the terminal device 1 may notrelease (remove) the information associated with the ON/OFF cell. Forexample, in the OFF state of the ON/OFF cell, the terminal device 1 mayretain the information associated with the ON/OFF cell, and may reusethe information associated with the ON/OFF cell when the ON/OFF cell isin the ON state.

The ON/OFF cell being in the OFF state and the ON/OFF cell beingdeactivated may be the same, and the deactivation of the ON/OFF cell maybe the same as the deactivation (deactivation of the non-ON/OFF cell) ofthe related art.

The OFF state of the ON/OFF cell and the deactivation of the related artmay be simultaneously performed.

If the base station device 3 notifies the terminal device 1 of the OFFstate of the ON/OFF cell by the L1 signalling (DCI format) or the L2signalling (MAC CE) whenever the ON/OFF cell performs transition fromthe ON state to the OFF state (the base station device 3 performstransition from the activated state to the deactivated state), theoverhead of the control information is increased.

However, if the ON state/OFF state of the ON/OFF cell is notified to theterminal device 1 whenever the ON/OFF cell performs transition from theON state to the OFF state, the terminal device 1 excessively consumesthe battery in order to perform the operation such as the monitoring ofthe PDCCH in the ON/OFF cell in the OFF state until the OFF state timerof the cell in the OFF state expires.

Thus, in a case where the base station device 3 uses the ON/OFF cell, acase where the terminal device 1 implicitly determines (assumes) the OFFstate of the ON/OFF cell and the terminal device 1 implicitly recognizesthe ON/OFF cell determined (assumed) to be in the OFF state as the OFFstate (implicit deactivation), or a case where the terminal deviceperforms transition to the operation in a case where the communicationwith the ON/OFF cell in the OFF state is performed in the ON/OFF celldetermined (assumed) to be in the OFF state is effective. For example,the operation in the case where the communication with the ON/OFF statein the OFF state is performed is an operation assumed that at least oneof the PSS/SSS, the CRS, the CSI-RS, the PBCH, the PDCCH, the EPDCCH andthe PDSCH is not transmitted. For example, the operation in the casewhere the communication with the ON/OFF cell in the OFF state isperformed may be a state in which the terminal device 1 performs aprocess different from that of the terminal device of the related art.For example, the operation in the case where the communication with theON/OFF cell in the OFF state is performed may be an operation in whichthe terminal device 1 performs only the uplink transmission of the PUCCHor the PUSCH.

The terminal device 1 may receive information indicating whether or notthe cell configured for the terminal device 1 is the ON/OFF cell fromthe base station device 3. That is, the base station device 3 maytransmit the information indicating whether or not the cell configuredfor the terminal device 1 is the ON/OFF cell to the terminal device 1.

An example of the implicit OFF state of the ON/OFF cell will bedescribed.

The terminal device 1 reports the channel quality indicator(CQI)/precoding matrix indicator (PMI)/rank indicator (RI)/precodingtype indicator (PTI) for the ON/OFF cell for which the ON state isconfigured. That is, in a case where the ON/OFF cell performs transitionfrom the ON state to the OFF state, information associated with thecalculation of the channel quality indicator (CQI)/precoding matrixindicator (PMI)/rank indicator (RI)/precoding type indicator (PTI) ismeasured until the OFF state timer associated with the ON/OFF cellexpires or the OFF state of the ON/OFF cell is notified by the basestation device 3.

In the ON/OFF cell in the OFF state, the reference signal (CRS, CSI-RSor DRS) used by the terminal device 1 to measure the informationassociated with the calculation of the channel quality indicator(CQI)/precoding matrix indicator (PMI)/rank indicator (RI)/precodingtype indicator (PTI) is not transmitted in some cases. That is, if theterminal device 1 calculates the channel quality indicator(CQI)/precoding matrix indicator (PMI)/rank indicator (RI)/precodingtype indicator (PTI) for the ON/OFF cell in the OFF state, a possibilitythat a specific channel quality indicator (CQI)/precoding matrixindicator (PMI)/rank indicator (RI)/precoding type indicator (PTI) iscalculated becomes high. Thus, if the terminal device 1 calculates thespecific channel quality indicator (CQI)/precoding matrix indicator(PMI)/rank indicator (RI)/precoding type indicator (PTI) a predeterminednumber of times or more in the ON/OFF cell for which the ON state isconfigured, the reference signal is not transmitted in the ON/OFF cell,that is, it is determined (assumed) that the base station device 3 is inthe OFF state and it is recognized that the ON/OFF cell is in the OFFstate (performs transition to an operation in a case where thecommunication with the ON/OFF cell in the OFF state is performed).

For example, in a case where “out of range (out of allowable range)” iscalculated a predetermined number of times, in a case where “out ofrange (out of allowable range)” is calculated in subframes in which apredetermined number of subframes are continued a predetermined numberof times, or in a case where “out of range (out of allowable range)” issuccessively calculated a predetermined number of times, the ON/OFF cellmay be recognized as the OFF state (transition to the operation in whichthe communication with the ON/OFF cell in the OFF state is performed inthe ON/OFF cell may be performed).

The predetermined number of subframes and the predetermined number oftimes with which the terminal device 1 determines the OFF state of theON/OFF cell may be previously defined, or may be notified from the basestation device 3.

An example of the implicit OFF state of the ON/OFF cell will bedescribed.

The DRS is not transmitted in the ON/OFF cell in the OFF state in somecases. In a case where the DRS is not detected in the ON/OFF cell forwhich the ON state is configured or in a case where the reception powerof the resource assumed that the DRS is transmitted does not athreshold, the terminal device 1 does not transmit the DRS in the ON/OFFstate, that is, determines (assumes) that the base station device 3 isin the OFF state and recognizes that the ON/OFF cell is in the OFF state(performs transition to the operation in a case where the communicationwith the ON/OFF cell in the OFF state is performed in the ON/OFF cell).

For example, in a case where the DRS is not detected a predeterminednumber of times, in a case where the DRS is not detected in thesubframes in which a predetermined number of subframes is continued apredetermined number of times, or in a case where the DRS is notsuccessively detected a predetermined number of times, it may berecognized that the ON/OFF cell is in the OFF state (transition to theoperation in a case where the communication with the ON/OFF cell in theOFF state in the ON/OFF cell may be performed).

The case where the RS is not detected is a case where the average powerof the RE to which the RS is mapped does not exceed a threshold. The REof which the power is calculated may be averaged over the plurality ofsubframes. The RE of which the power is calculated may be averaged onlyin a specific subframe. The RE of which the power is calculated may beaveraged in a partial resource block having the system bandwidth, andmay not be averaged in a partial resource block.

The subframe in which a part or all of the RSs is not present isnotified to the terminal device 1. The terminal device 1 does not addthe average of the power calculated for the RE in which the RS is notpresent in the subframe in which a part or all of the RSs is notpresent.

The predetermined number of subframes and/or the predetermined number oftimes with which the terminal device 1 determines the OFF state of theON/OFF cell may be previously defined, or may be notified from the basestation device 3.

In a case where the DRS is not detected, the determination may beperformed based on the RSRP and/or RSRQ.

In a case where the DRS is not detected, the determination may beperformed by comparing the average reception power of the subframe orthe reception power of the resource assumed that the DRS is transmittedwith a predetermined threshold. The predetermined threshold may bepreviously defined, or may be notified from the base station device 3.

A DRS pattern indicating the ON state and a DRS pattern indicating theOFF state may be independently defined, and in a case where the DRSpattern indicating the OFF state is detected, it may be recognized thatthe ON/OFF cell is in the OFF state (transition to the operation in acase where the communication with the ON/OFF cell in the OFF state inthe ON/OFF cell may be performed). That is, the base station device 3may transmit the DRS using a different DRS pattern between the ON stateand the OFF state.

An example of the implicit OFF state of the ON/OFF cell will bedescribed.

The CRS is not transmitted in the ON/OFF cell in the OFF state in somecases. In a case where the CRS is not detected in the ON/OFF cell forwhich the ON state is configured, or in a case where the reception powerof the resource assumed that the CRS is transmitted does not athreshold, the terminal device 1 does not transmit the CRS in the ON/OFFcell, that is, determines (assumes) that the base station device 3 is inthe OFF state and recognizes that the ON/OFF cell is in the OFF state(performs transition to the operation in a case where the communicationwith the ON/OFF cell in the OFF state is performed in the ON/OFF cell).

For example, in a case where the CRS is not detected a predeterminednumber of times, in a case where the CRS is not detected in thesubframes in which a predetermined number of subframes are continued apredetermined number of times, in a case where the CRS is notsuccessively detected a predetermined number of times, it may berecognized that the ON/OFF cell is in the OFF state (transition to theoperation in which the communication with the ON/OFF cell in the OFFstate is performed in the ON/OFF cell may be performed).

The predetermined number of subframes and/or the predetermined number oftimes with which the terminal device 1 determines the OFF state of theON/OFF cell may be previously defined, or may be notified from the basestation device 3.

In a case where the CRS is not detected, the determination may beperformed based on the RSRP and/or the RSRQ.

In a case where the CRS is not detected, the determination may beperformed by comparing the average reception power of the subframes orthe reception power of the resource assumed that the CRS is transmittedwith a predetermined threshold. The predetermined threshold may bepreviously defined, or may be notified from the base station device 3.

In a case where a CRS pattern indicating the ON state and a CRS patternindicating the OFF state are independently defined and the CRS patternindicating the OFF state is detected, it may be recognized that theON/OFF cell is in the OFF state (transition to the operation in a casewhere the communication with the ON/OFF cell in the OFF state isperformed in the ON/OFF cell may be performed). That is, the basestation device 3 may transmit the CRS by using a CRS pattern between theON state and the OFF state.

An example of the implicit OFF state of the ON/OFF cell will bedescribed.

The terminal device 1 monitors the PDCCH/EPDCCH in the ON/OFF cell forwhich the ON state is configured. In a case where the PDCCH/EPDCCH isnot successively detected over a predetermined number of subframes ormore in the ON/OFF cell for which the ON state is configured, theterminal device 1 determines (assumes) that the base station device 3 isin the OFF state, and recognizes that the ON/OFF cell is in the OFFstate (performs transition to the operation in a case where thecommunication with the ON/OFF cell in the OFF state is performed in theON/OFF cell). That is, in a case where the PDCCH/EPDCCH is notsuccessively detected over a predetermined number of subframes or morein the search space based on the value of the CIF associated with theON/OFF cell for which the ON state is configured, the terminal device 1determines (assumes) that the base station device 3 is in the OFF state,recognizes that the ON/OFF cell is in the OFF state (performs transitionto the operation in a case where the communication with the ON/OFF cellin the OFF state is performed in the ON/OFF cell). That is, the basestation device 3 does not arrange the PDCCH/EPDCCH in the search spacebased on the value of the CIF associated with the ON/OFF cell for whichthe OFF state is configured.

The predetermined number of subframes with which the terminal device 1determines the OFF state of the ON/OFF cell may be previously defined,or may be notified from the base station device 3.

In a case where the PDCCH/EPDCCH is not detected, an error is notdetected by a cyclic redundancy check (CRC) or the average receptionpower of the subframes is compared with a predetermined threshold, andthus, the determination may be performed. The predetermined thresholdmay be previously defined or may be notified from the base stationdevice 3.

An example of the implicit OFF state of the ON/OFF cell will bedescribed.

In a case where the PDCCH/EPDCCH indicating the downlink grant for theON/OFF cell for which the ON state is configured or the uplink grant forthe ON/OFF cell for which the ON state is configured in the ON/OFF cellfor which the ON state is configured is not successively detected over apredetermined number of subframes or, the terminal device 1 determines(assumes) that the base station device 3 is in the OFF state, andrecognizes that the ON/OFF cell in the OFF state (perform transition tothe operation in a case where the communication with the ON/OFF cell inthe OFF state is performed in the ON/OFF cell).

The predetermined number of subframes with which the terminal device 1determines the OFF state of the ON/OFF cell may be previously defined,or may be notified from the base station device 3.

An example of the implicit OFF state of the ON/OFF cell will bedescribed.

In a case where the PDCCH/EPDCCH indicating the downlink grant for theON/OFF cell for which the ON state is configured or the uplink grant forthe ON/OFF cell for which the ON state is configured is not successivelydetected over a predetermined number of subframes or more in the servingcell that schedules the ON/OFF cell for which the ON state isconfigured, the terminal device 1 determines (assumes) that the basestation device 3 is in the OFF state, and recognizes that the ON/OFFcell is in the OFF state (perform transition to the operation in a casewhere the communication with the ON/OFF cell in the OFF state isperformed in the ON/OFF cell). That is, in a case where the PDCCH/EPDCCHindicating the downlink grant for the ON/OFF cell for which the ON stateis configured or the uplink grant for the ON/OFF cell for which the ONstate is configured is not successively detected over a predeterminednumber of subframes or more in the search space based on the value ofthe CIF associated with the ON/OFF cell for which the ON state isconfigured, the terminal device 1 determines (assumes) that the basestation device 3 is in the OFF state, and recognizes that the ON/OFFcell is in the Off state (performs transition to the operation in a casewhere the communication with the ON/OFF cell in the OFF state isperformed in the ON/OFF cell). That is, the base station device 3 doesnot arrange the PDCCH/EPDCCH indicating the downlink grant for theON/OFF cell for which the ON state is configured or the uplink grant forthe ON/OFF cell for which the ON state is configured in the search spacebased on the value of the CIF associated with the ON/OFF cell for whichthe OFF state is configured.

The predetermined number of subframes with which the terminal device 1determines the OFF state of the ON/OFF cell may be previously defined,or may be notified from the base station device 3.

An example of the implicit OFF state of the ON/OFF cell will bedescribed.

In a case where discontinuous reception (DRX) is configured for theON/OFF cell for which the ON state is configured, the terminal device 1determines (assumes) that the base station device 3 is in the OFF state,and recognizes that the ON/OFF cell is in the OFF state (performstransition to the operation in a case where the communication with theON/OFF cell in the OFF state is performed in the ON/OFF cell).

In a case where a parameter related to short DRX is configured, it ispreferable that the terminal device 1 determines (assumes) that the basestation device 3 is in the ON state and does not recognize that theON/OFF cell in the OFF state (it is preferable that transition to theoperation in a case where the communication with the ON/OFF cell in theOFF state is performed in the ON/OFF cell is not performed).

Discontinuous reception (DRX) for the ON/OFF cell may be independentlyconfigured for each ON/OFF cell.

A timer associated with duration of discontinuous reception (DRX) forthe ON/OFF cell may be configured on a per subframe basis.

An example of the implicit OFF state of the ON/OFF cell will bedescribed.

In the ON/OFF cell in the OFF state, the PHICH is not transmitted (theHARQ indicator (HARQ feedback or response information) indicatingacknowledgement (ACK) or negative acknowledgement (NACK) for the uplinkdata (uplink shared channel: UL-SCH) transmitted by the terminal device1 is not transmitted) in some cases. In a case where the PHICH is notdetected in the ON/OFF cell for which the ON state is configured (theHARQ indicator (HARQ feedback or response information) indicating theacknowledgement (ACK) or negative acknowledgement (NACK) for the uplinkdata (uplink shared channel: UL-SCH) transmitted by the terminal device1 is not detected), the terminal device 1 determines (assumes) that thebase station device 3 is in the OFF state, and recognizes that theON/OFF cell is in the OFF state (performs transition to the operation ina case where the communication with the ON/OFF cell in the OFF state isperformed in the ON/OFF cell).

For example, in a case where the PHICH is not detected a predeterminednumber of times, in a case where the PHICH is not detected in thesubframes in which a predetermined number of subframes are continued apredetermined number of times, or in a case where the PHICH is notsuccessively detected a predetermined number of times, it may berecognized that the ON/OFF cell is in the OFF state (transition to theoperation in a case where the communication with the ON/OFF cell in theOFF state is performed in the ON/OFF cell may be performed).

The predetermined number of subframes and/or the predetermined number oftimes with which the terminal device 1 determines the OFF state of theON/OFF cell may be previously defined, or may be notified from the basestation device 3.

In a case where the PHICH is not detected, the determination may beperformed by comparing the average reception power of the subframes orthe reception power of the resource assumed that the PHICH istransmitted with a predetermined threshold. The predetermined thresholdmay be previously defined, or may be notified from the base stationdevice 3.

The example of the implicit OFF state of the ON/OFF cell is not limitedto the case where the OFF state is individually performed, and two ormore OFF states may be simultaneously performed, or may besimultaneously performed with another deactivation defined by thespecifications.

The OFF state of the ON/OFF cell determined (assumed) to be in the OFFstate (transition to the operation in a case where the communicationwith the ON/OFF cell in the OFF state is performed) may be applied to aradio frame and/or a subframe determined (assumed) to be in the OFFstate, or may be applied to a radio frame and/or a subframe which ispositioned after a predetermined number of radio frames or apredetermined number of subframes from the radio frame and/or thesubframe determined (assumed) to be in the OFF state.

The predetermined number of radio frames or the predetermined number ofsubframes before the OFF state of the ON/OFF cell determined (assumed)to be in the OFF state is applied (transition to the operation in a casewhere the communication with the ON/OFF cell in the OFF state isperformed) may be previously defined, or may be notified from the basestation device 3.

Hereinafter, the implicit ON state (implicit activation) of the ON/OFFcell will be described.

The ON state of the base station device 3 is a state in which theterminal device 1 can perform the same process as that of the terminaldevice of the related art. A specific example of the ON state of thebase station device 3 is as follows. The terminal device 1 expects toreceive the PSS, the SSS and the PBCH. The terminal device 1 monitorsthe PDCCH and/or the EPDCCH in a predetermined subframe. The terminaldevice 1 performs the CSI reporting based on the configured CSIreporting mode. The terminal device 1 expects that the CSI referenceresource and the reference signal (for example, CRS or CSI-RS) for theCSI reporting are present.

In the ON state of the ON/OFF cell, the terminal device 1 may useinformation which is retained in the OFF state and is associated withthe ON/OFF cell again.

The ON/OFF cell being in the ON state and the ON/OFF cell beingactivated may be the same, or the activation of the ON/OFF cell may bethe same as the activation (activation of the non-ON/OFF cell) of therelated art.

The ON state of the ON/OFF cell and the activation of the related artmay be simultaneously performed.

If the base station device 3 notifies the terminal device 1 of the ONstate of the ON/OFF cell by the L1 signalling (DCI format) or the L2signalling (MAC CE) whenever the ON/OFF cell performs transition to theON state from the OFF state (the base station device 3 performstransition to the activated state from the deactivated state), theoverhead of the control information is increased.

Thus, in a case where the base station device 3 uses the ON/OFF cell, acase where the terminal device 1 implicitly determines (assumes) the ONstate of the ON/OFF cell and the terminal device 1 implicitly changesthe ON/OFF cell determined (assumed) to be in the ON state to the ONstate (implicit activation) or a case where the terminal device performstransition in a case where the communication with the ON/OFF cell in theON state is performed is effective. For example, the operation in thecase where the communication with the ON/OFF cell in the ON state may bean operation in which the terminal device 1 uses information which isretained in the OFF state of the ON/OFF cell and is associated with theON/OFF cell again. The operation in the case where the communicationwith the ON/OFF cell in the ON state may be an operation in which theterminal device 1 can perform the same process as that in the terminaldevice of the related art.

The terminal device 1 may receive information indicating whether or notthe cell configured for the terminal device 1 is the ON/OFF cell fromthe base station device 3. That is, the base station device 3 maytransmit the information indicating whether or not the cell configuredfor the terminal device 1 is the ON/OFF cell to the terminal device 1.

An example of the implicit ON state of the ON/OFF cell will bedescribed.

In the ON/OFF cell in the OFF state, the DRS is not transmitted in somecases, that is, the DRS is transmitted only in the ON state of theON/OFF cell in some cases. In a case where the DRS is detected in theON/OFF cell for which the OFF state is configured, or in a case wherethe reception power of the resource assumed that the DRS is transmittedexceeds a threshold, the terminal device 1 transmit the DRS in theON/OFF cell, that is, determines (assumes) that the base station device3 is in the ON state, and recognizes that the ON/OFF cell is in the ONstate (performs transition to the operation in a case where thecommunication with the ON/OFF cell in the ON state is performed in theON/OFF cell).

In a case where the DRS is detected, the determination may be performedbased on the RSRP and/or the RSRQ.

In a case where the DRS is detected, the determination may be performedby comparing the average reception power of the subframes or thereception power of the resource assumed that the DRS is transmitted witha predetermined threshold. The predetermined threshold may be previouslydefined, or may be notified from the base station device 3.

A DRS pattern indicating the ON state and a DRS pattern indicating theOFF state may be independently defined, and in a case where the DRSpattern indicating the ON state is detected, it may be recognized thatthe ON/OFF cell is in the ON state (transition to the operation in acase where the communication with the ON/OFF cell in the ON state isperformed in the ON/OFF cell may be performed). That is, the basestation device 3 may transmit the DRS by using a different DRS patternbetween the ON state and the OFF state.

An example of the implicit ON state of the ON/OFF cell will bedescribed.

In the ON/OFF cell in the ON state, the DRS is not transmitted in somecases, that is, the DRS is transmitted only in the OFF state of theON/OFF cell in some cases. In a case where the DRS is not detected inthe ON/OFF cell for which the OFF state is configured, or in a casewhere the reception power of the resource assumed that the DRS istransmitted does not exceed a threshold, the terminal device 1 does nottransmit the DRS in the ON/OFF cell, that is, determines (assumes) thatthe base station device 3 is in the ON state, and recognizes that theON/OFF cell is in the ON state (performs transition to the operation ina case where the communication with the ON/OFF cell in the ON state isperformed in the ON/OFF cell).

In a case where the DRS is not detected, the determination may beperformed based on the RSRP and/or the RSRQ.

In a case where the DRS is not detected, the determination may beperformed by comparing the average reception power of the subframes orthe reception power of the resource assumed that the DRS is transmittedwith a predetermined threshold. The predetermined threshold may bepreviously defined, or may be notified from the base station device 3.

An example of the implicit ON state of the ON/OFF cell will bedescribed.

In the ON/OFF cell in the OFF state, the CRS is not transmitted in somecases, that is, the CRS is transmitted only in the ON state of theON/OFF cell in some cases. In a case where the CRS is detected in theON/OFF cell for which the OFF state is configured, or in a case wherethe reception power of the resource assumed that the CRS is transmittedexceeds a threshold, the terminal device 1 transmits the CRS in theON/OFF cell, that is, determines (assumes) that the base station device3 is in the ON state, and recognizes that the ON/OFF cell is in the ONstate (performs transition to the operation in a case where thecommunication with the ON/OFF cell in the ON state is performed in theON/OFF cell).

In a case where the CRS is detected, the determination may be performedbased on the RSRP and/or the RSRQ.

In a case where the CRS is detected, the determination may be performedby comparing the average reception power of the subframes or thereception power of the resource assumed that the CRS is transmitted witha predetermined threshold. The predetermined threshold may be previouslydefined, or may be notified from the base station device 3.

A CRS pattern indicating the ON state and a CRS pattern indicating theOFF state are independently defined, and in a case where the CRS patternindicating the ON state is detected, it may be recognized that theON/OFF cell is in the ON state (transition to the operation in a casewhere the communication with the ON/OFF cell in the ON state isperformed in the ON/OFF cell may be performed). That is, the basestation device 3 may transmit the CRS by using a different CRS patternbetween the ON state and the OFF state.

An example of the implicit ON state of the ON/OFF cell will bedescribed.

In a case where the PDCCH/EPDCCH indicating the downlink grant for theON/OFF cell for which the OFF state is configured or the uplink grantfor the ON/OFF cell for which the OFF state is configured in the servingcell that schedules the ON/Off cell for which the OFF state isconfigured is detected, the terminal device 1 determines (assumes) thatthe base station device 3 is in the ON state, and recognizes that theON/OFF cell is in the ON state (performs transition to the operation ina case where the communication with the ON/OFF cell in the ON state isperformed in the ON/OFF cell).

It is preferable that the PDCCH/EPDCCH indicating the downlink grant forthe ON/OFF cell for which the OFF state is configured or the uplinkgrant for the ON/OFF cell for which the OFF state is configured in theserving cell that schedules the ON/OFF cell for which the OFF state isconfigured is not allocated to the search space based on the carrierindicator field (CIF) associated with the ON/OFF cell for which the OFFstate is configured (it is preferable that the PDCCH/EPDCCH is allocatedto the search space based on the carrier indicator field (CIF)associated with the cell for which the ON state is configured).

It is preferable that the PDCCH/EPDCCH indicating the downlink grant forthe ON/OFF cell for which the OFF state is configured or the uplinkgrant for the ON/OFF cell for which the OFF state is configured in theserving cell that schedules the ON/OFF cell for which the OFF state isconfigured is CRC-masked with the RNTI associated with the ON/OFF cellfor which the OFF state is configured.

It is preferable that the PDCCH/EPDCCH indicating the downlink grant forthe ON/OFF cell for which the OFF state is configured or the uplinkgrant for the ON/OFF cell for which the OFF state is configured in theserving cell that schedules the ON/OFF cell for which the OFF state isconfigured is a payload size including bit information related to thecarrier indicator field (CIF) associated with the ON/OFF cell for whichthe OFF state is configured.

An example of the implicit ON state of the ON/OFF cell will bedescribed.

In a case where the timer associated with the discontinuous reception(DRX) for the ON/OFF cell for which the OFF state is configured expires,the terminal device 1 determines (assumes) that the base station device3 is in the ON state, and recognizes that the ON/OFF cell is in the ONstate (performs transition to the operation in a case where thecommunication with the ON/OFF cell in the ON state is performed in theON/OFF cell).

The discontinuous reception (DRX) for the ON/OFF cell may beindependently configured for each ON/OFF cell.

The timer associated with the duration of the discontinuous reception(DRX) for the ON/OFF cell may be configured on a per subframe basis.

An example of the implicit ON state of the ON/OFF cell will bedescribed.

In a case where the timer associated with the short DRX for the ON/OFFcell for which the OFF state is configured expires, the terminal device1 determines (assumes) that the base station device 3 is in the ONstate, and recognizes that the ON/OFF cell is in the ON state (performstransition to the operation in a case where the communication with theON/OFF cell in the ON state is performed in the ON/OFF cell).

The short DRX for the ON/OFF cell may be independently configured foreach ON/OFF cell.

The timer associated with the duration of the short DRX for the ON/OFFcell may be configured on a per subframe basis.

The example of the implicit ON state of the ON/OFF cell is not limitedto the case where the ON state is individually performed, and two ormore ON states may be simultaneously performed, or may be simultaneouslyperformed with another activation defined by the specifications.

The ON state of the ON/OFF cell determined (assumed) to be in the ONstate (transition to the operation in a case where the communicationwith the ON/OFF cell in the ON state is performed) may be applied to aradio frame and/or a subframe determined (assumed) to be in the ONstate, or may be applied to a radio frame and/or a subframe which ispositioned after a predetermined number of radio frames or apredetermined number of subframes from the radio frame and/or thesubframe determined (assumed) to be in the ON state.

The predetermined number of radio frames or the predetermined number ofsubframes before the ON state of the ON/OFF cell determined (assumed) tobe in the ON state is applied (transition to the operation in a casewhere the communication with the ON/OFF cell in the ON state isperformed) may be previously defined, or may be notified from the basestation device 3.

The implicit ON state and/or implicit OFF state of the ON/OFF cell maybe performed in a case where the terminal device 1 waits for apredetermined function (capability or UE capability).

The implicit ON state and/or implicit OFF state of the ON/OFF cell maybe performed by the terminal device 1 in a predetermined mode. Forexample, in a case where an implicit/explicit activation mode isdefined, the implicit ON state and/or implicit OFF state of the ON/OFFcell may be performed in a case where the terminal device 1 is in theimplicit mode. It is preferable that the switching of theimplicit/explicit activation mode is notified using a R field reservedin the MAC CE, and it is preferable that a case where the R field is setto be “0” indicates the explicit activation mode and a case where the Rfield is set to be “1” indicates the implicit activation mode.

Hereinafter, the OFF state timer (OFF timer or small cell deactivationtimer) of the ON/OFF cell will be described.

In a case where the indication of the ON state of the ON/OFF cell isreceived, the terminal device 1 starts or restarts the OFF state timerassociated with the ON/OFF cell.

In a case where the PDCCH of the ON/OFF cell does not indicate thedownlink grant or the uplink grant, in a case where the PDCCH of theserving cell that schedules the ON/OFF cell does not indicate thedownlink grant for the ON/OFF cell or the uplink grant for the ON/OFFcell, or in a case where there is no indication of the PDCCH for theON/OFF cell, the terminal device 1 counts up the OFF state timerassociated with the ON/OFF cell (increases 1 or adds 1). In a case wherethe OFF state timer is present on a per radio frame basis, the timercounts up in all predetermined radio frames in a case where there is noindication of the PDCCH. In a case where the OFF state timer is presentfor a plurality of subframes, the timer counts up in all the pluralityof subframes in a case where there is no indication of the PDCCH.

The OFF state timer may count up only in a specific subframe. In otherwords, the OFF state timer does not count up in the subframes other thanthe specific subframe. For example, the OFF state timer does not countup in the uplink subframe even though the timer satisfies theabove-described condition. For example, the OFF state timer does notcount in the MBSFN subframe even though the timer satisfies theabove-described condition. For example, the OFF state timer does notcount up in the subframe indicated in the higher layer even though thetimer satisfies the above-described condition.

In a case where the OFF state timer associated with the ON/OFF cellexpires, the terminal device 1 recognizes that the ON/OFF cell is in theOFF state.

In a case where the PDCCH of the ON/OFF cell indicates the downlinkgrant or the uplink grant, or in a case where the PDCCH of the servingcell that schedules the ON/OFF cell indicates the downlink grant for theON/OFF cell or the uplink grant for the ON/OFF cell, the terminal device1 starts or restarts the OFF state timer associated with the ON/OFFcell.

In a case where the indication of the OFF state of the ON/OFF cell isreceived, or in a case where the OFF state timer associated with theON/OFF cell expires, the terminal device 1 stops the OFF timerassociated with the ON/OFF cell.

The OFF state timer of the ON/OFF cell may be the same as thedeactivation timer (timer associated with the duration of the cell). TheOFF state timer of the ON/OFF cell may be a timer associated with theduration of the ON/OFF cell.

In a case where the inter-cell interference is suppressed using theON/OFF cell, the ON state and the OFF state of the ON/OFF cell aredynamically switched depending on the position or traffic amount of theterminal device 1. As the switching speed between the ON state and theOFF state of the ON/OFF cell becomes higher, the adaptability for theposition or traffic amount of the terminal device 1 becomes high.

The ON/OFF cell and/or the non-ON/OFF cell may be configured for theprimary cell, may be configured for the secondary cell, or may beconfigured for the secondary cell (primary secondary cell or specialcell) having a special function (for example, a function of the primarycell) among the secondary cells.

The ON state may be constantly configured for the ON/OFF cell and/or thenon-ON/OFF cell.

That is, it is preferable that the ON/OFF cell and the non-ON/OFF cellare independently maintained in the terminal device 1. That is, aninitial value of the OFF state timer associated with the ON/OFF cell andan initial value of the deactivation timer associated with thenon-ON/OFF cell are independently configured.

An example of the configuration of the initial value of the OFF statetimer will be described.

The initial value of the OFF state timer associated with the ON/OFF cellmay be configured using a parameter of sCellDeactivationTimer-r12 fromthe higher layer (RRC layer), and the initial value of the deactivationtimer associated with the non-ON/OFF cell may be configured using aparameter of sCellDeactivationTimer-r10 from the higher layer (RRClayer).

An example of the configuration of the initial value of the OFF statetimer will be described.

The initial value of the OFF state timer associated with the ON/OFF celland the initial value of the deactivation timer associated with thenon-ON/OFF cell may be configured using two or more same parameters. Forexample, the initial value of the OFF state timer associated with theON/OFF cell and the initial value of the deactivation timer associatedwith the non-ON/OFF cell may be configured using two or more parametersof sCellDeactivationTimer-r10.

An example of the configuration of the initial value of the OFF statetimer will be described.

The initial value of the OFF state timer associated with the ON/OFF cellmay be configured by replacing the initial value of the OFF state timerassociated with the ON/OFF cell with the parameter ofsCellDeactivationTimer-r10 associated with the initial value of thedeactivation timer associated with the non-ON/OFF cell. For example, ina case where rf2 which is a value associated with the number of radioframes is configured for the parameter of sCellDeactivationTimer-r10,the initial value of the OFF state timer associated with the ON/OFF cellmay be configured by being replaced with rf1.

The parameter of sCellDeactivationTimer-r10 associated with the initialvalue of the deactivation timer associated with the non-ON/OFF cell maybe configured as the initial value of the OFF state timer associatedwith the ON/OFF cell.

It is preferable that at least one of rf2, rf4, rf8, rf16, rf32, rf64and rf128 which are values associated with the number of radio frames isconfigured for the parameter of sCellDeactivationTimer-r12 and theparameter of sCellDeactivationTimer-r10. Here, rf2 corresponds to 2radio frames, rf4 corresponds to 4 radio frames, rf8 corresponds to 8radio frames, rf16 corresponds to 16 radio frames, rf32 corresponds to32 radio frames, rf64 corresponds to 64 radio frames, and rf128corresponds to 128 radio frames.

The values associated with the number of radio frames configured for theparameter of sCellDeactivationTimer-r12 and the parameter ofsCellDeactivationTimer-r10 may be selected from different values. Forexample, it is preferable that at least one of rf2, rf4, rf8, rf16,rf32, rf64 and rf128 which are values associated with the number ofradio frames is configured for the parameter ofsCellDeactivationTimer-r10 and at least one of rf1, rf2, rf4, rf8, rf16,rf32 and rf64 which are values associated with the number of radioframes is configured for the parameter of sCellDeactivationTimer-r12.Here, rf1 corresponds to one radio frame, rf2 corresponds to 2 radioframes, rf4 corresponds to 4 radio frames, rf8 corresponds to 8 radioframes, rf16 corresponds to 16 radio frames, rf32 corresponds to 32radio frames, rf64 corresponds to 64 radio frames, and rf128 correspondsto 128 radio frames.

The values configured for the parameter of sCellDeactivationTimer-r12and the parameter of sCellDeactivationTimer-r10 may be selected fromvalues associated with the number of subframes.

The initial value of the OFF state timer may be applied to a radio frameand/or a subframe in which the configuration is received, or may beapplied to a radio frame and/or a subframe which is positioned after apredetermined number of radio frames or a predetermined number ofsubframes from the radio frame and/or the subframe in which theconfiguration is received.

In a case where an initial value of a second OFF state timer isconfigured for the terminal device 1 for which an initial value of afirst OFF state timer is configured, the initial value may be applied toa radio frame and/or a subframe in which the configuration of theinitial value of the second OFF state timer is received, or may beapplied to a radio frame or a subframe which is positioned after apredetermined number of radio frames or a predetermined number ofsubframes from the radio frame and/or the subframe in which theconfiguration of the initial value of the second OFF state timer isreceived, or the initial value of the second OFF state timer may beignored.

The predetermined number of radio frames or the predetermined number ofsubframes to which the initial value of the OFF state timer is appliedmay be previously defined, or may be notified from the base stationdevice 3.

The initial value of the OFF state timer associated with the ON/OFF cellmay be configured using the higher layer (RRC layer).

The initial value of the OFF state timer associated with the ON/OFF cellmay be configured using the L1 signalling (for example, DCI format). Forexample, the initial value of the OFF state timer associated with theON/OFF cell may be configured using the L1 signalling (for example, DCIformat), and the initial value of the deactivation timer associated withthe non-ON/OFF cell may be configured using the higher layer (RRClayer).

In a case where a plurality of ON/OFF cells is configured for theterminal device 1, as the initial value of the OFF state timerassociated with the ON/OFF cell, a value common to the plurality ofconfigured ON/OFF cells may be configured, individual values for theplurality of configured ON/OFF cells may be configured, or a valuecommon to groups acquired by grouping the plurality of configured ON/OFFcells may be configured.

Hereinafter, the details of the CSI measurement and CSI reporting of theterminal device 1 will be described.

The CSI includes a channel quality indicator (CQI), a precoding matrixindicator (PMI), a precoding type indicator (PTI) and/or a rankindicator (RI). The RI indicates the number of transmission layers (thenumber of ranks). The PMI is information indicating a predefinedprecoding matrix. The PMI indicates one precoding matrix by using oneinformation item or two information items. The PMI in a case where twoinformation items are used is referred to as a first PMI and a secondPMI. The CQI is information indicating the combination of a predefinedmodulation scheme and coding rate. The terminal device reports arecommended CSI to the base station device 3. The terminal device 2reports the CQI that satisfies predetermined reception quality for eachtransport block (code word).

The subframe (reporting instances) in which the CSI reporting can beperiodically performed is determined by a reporting cycle and a subframeoffset based on the information (CQI PMI index or RI index) configuredin the higher layer. The information configured in the higher layer canbe configured for each subframe set configured in order to measure theCSI. In a case where only one information item is configured for aplurality of subframe sets, the information may be regarded as beingcommon to the subframe sets.

One P-CSI reporting event to each serving cell is configured for theterminal device 2 configured in Transmission Modes 1 to 9 by the higherlayer signalling.

One or more P-CSI reporting events to each serving cell are configuredfor the terminal device 2 configured in Transmission Mode 10 by higherlayer signalling.

Eight CSI-RS ports are configured for the terminal device 2 configuredin Transmission Mode 9 or 10, and a reporting mode (Mode 1-1) of asingle PMI in a feedback CQI is configured in Submode 1 or Submode 2using a certain parameter (PUCCH_format-1-1_CSI_reporting_mode) by thehigher layer signalling.

The CQI reporting in a certain subframe of a certain serving cell for aUE-selected subband CQI is to report channel quality in a specificportion (a part) of a bandwidth of the serving cell indicated as abandwidth part.

A CSI reporting type supports a PUCCH CSI reporting mode. The CSIreporting type is referred to as a PUCCH reporting type in some cases.Type 1 reporting supports CQI feedback for the UE-selected subband. Type1a reporting supports a subband CQI and second PMI feedback. Type 2,type 2b and type 2c reporting events support a feedback CQI and PMIfeedback. Type 2a reporting supports feedback PMI feedback. Type 3reporting supports RI feedback. Type 4 reporting supports a feedbackCQI. Type 5 reporting supports RI and feedback PMI feedback. Type 6reporting supports RI and PTI feedback.

Hereinafter, the details of the CSI measurement and CSI reporting of theterminal device 1 in the base station device 3 that supports the ONstate and the OFF state will be described.

Information related to the CSI measurement and CSI reporting isconfigured for the terminal device 1 from the base station device 3. TheCSI measurement is performed based on the reference signal and/or thereference resource (for example, CRS, CSI-RS, CSI-IM resource and/orDRS). The reference signal used in the CSI measurement is determinedbased on the configuration of the transmission mode. The CSI measurementis performed based on the channel measurement and the interferencemeasurement. For example, the channel measurement is to measure thepower of a desired cell. The interference measurement is to measure thepower and noise power in cells other than the desired cell.

As an example, the terminal device 1 performs the channel measurementand the interference measurement based on the CRS. As another example,the terminal device 1 performs the channel measurement based on theCSI-RS, and performs the interference measurement based on the CRS. Asanother example, the terminal device 1 performs the channel measurementbased on the CSI-RS, and performs the interference measurement based onthe CSI-IM resource. As another example, the terminal device 1 performsthe channel measurement and the interference measurement based on theDRS.

The terminal device 1 may perform the CSI measurement in considerationof the ON state and the OFF state of the base station device 3. Forexample, the terminal device 1 may take account of the ON state and theOFF state of the base station device 3 for the reference signal and/orthe reference resource for performing the CSI measurement. In thefollowing description, the reference signal in the CSI measurement alsoincludes the reference resource.

Particularly, the reference signal for the interference measurement maybe replaced with the resource to be referred to in order to perform theinterference measurement. That is, a signal may not be mapped to theresource for performing the interference measurement. Thus, it ispossible to determine whether the resource for performing theinterference measurement is valid or invalid depending on the ON stateand the OFF state of the base station device 3.

As an example, in the CSI measurement, the terminal device 1 assumesthat the reference signal for the channel measurement is transmittedonly in the ON state of the base station device 3 and the referencesignal for the interference measurement is transmitted only in the ONstate of the base station device 3. That is, the terminal device 1assumes that the reference signal for the channel measurement istransmitted in the subframe in the ON state of the base station device 3and the reference signal for the channel measurement is not transmittedin the subframe in the OFF state of the base station device 3. Theterminal device 1 assumes that the reference signal for the interferencemeasurement is transmitted in the subframe in the ON state of the basestation device 3 and the reference signal for the interferencemeasurement is not transmitted in the subframe in the OFF state of thebase station device 3. In other words, the terminal device 1 performsthe channel measurement based on the reference signal transmitted in apredetermined subframe of the subframes in the ON state of the basestation device 3, and performs the interference measurement based on thereference signal transmitted in a predetermined subframe of thesubframes in the ON state of the base station device 3. Accordingly, inthe OFF state, the base station device 3 may stop the reference signalfor the CSI measurement in the terminal device 1.

As another example, in the CSI measurement, the terminal device 1assumes that the reference signal for the channel measurement istransmitted only in the ON state of the base station device 3 and thereference signal for the interference measurement is transmitted in theON state and the OFF state of the base station device 3. That is, theterminal device 1 assumes that the reference signal for the channelmeasurement is transmitted in the subframe in the ON state of the basestation device 3 and the reference signal for the channel measurement isnot transmitted in the subframe in the OFF state of the base stationdevice 3. The terminal device 1 assumes that the reference signal forthe interference measurement is transmitted in the subframe of the ONstate and the OFF state of the base station device 3. In other words,the terminal device 1 performs the channel measurement based on thereference signal transmitted in a predetermined subframe of thesubframes in the ON state of the base station device 3, and performs theinterference measurement based on the reference signal transmitted in apredetermined subframe of the subframes in the ON state and the OFFstate of the base station device 3. Accordingly, in the OFF state, thebase station device 3 may stop the reference signal for the channelmeasurement in the terminal device 1. Since the terminal device 1 canperform the interference measurement irrespective of the ON state or theOFF state of the base station device 3, in a case where the terminaldevice 1 performs a process such as averaging in a time direction in theinterference measurement, it is possible to improve the accuracy of theprocess.

As another example, in the CSI measurement, the terminal device 1assumes that the reference signal for the channel measurement istransmitted in the ON state and the OFF state of the base station device3 and the reference signal the interference measurement is transmittedonly in the ON state of the base station device 3. That is, the terminaldevice 1 assumes that the reference signal for the channel measurementis transmitted in the subframe in the ON state and the OFF state of thebase station device 3. The terminal device 1 assumes that the referencesignal for the interference measurement is transmitted in the subframein the ON state of the base station device 3 and the reference signalfor the interference measurement is not transmitted in the subframe inthe OFF state of the base station device 3. In other words, the terminaldevice 1 performs the channel measurement based on the reference signaltransmitted in a predetermined subframe of the subframes in the ON stateand the OFF state of the base station device 3, and performs theinterference measurement based on the reference signal transmitted in apredetermined subframe of the subframes in the ON state of the basestation device 3. Accordingly, in the OFF state, the base station device3 may stop the reference signal for the interference measurement in theterminal device 1. Since the terminal device 1 can perform the channelmeasurement irrespective of the ON state or the OFF state of the basestation device 3, in a case where the terminal device 1 performs aprocess such as averaging in a time direction in the channelmeasurement, it is possible to improve the accuracy of the process.

As another example, in the CSI measurement, the terminal device 1assumes that the reference signal for the channel measurement istransmitted in the ON state and the OFF state of the base station device3 and the reference signal for the interference measurement istransmitted in the ON state and the OFF state of the base station device3. That is, the terminal device 1 assumes that the reference signal forthe channel measurement is transmitted in the subframe in the ON stateand the OFF state of the base station device 3. The terminal device 1assumes that the reference signal for the interference measurement istransmitted in the subframe in the ON state and the OFF state of thebase station device 3. In other words, the terminal device 1 performsthe channel measurement based on the reference signal transmitted in apredetermined subframe of the subframes in the ON state and the OFFstate of the base station device 3, and performs the interferencemeasurement based on the reference signal transmitted in a predeterminedsubframe of the subframes in the ON state and the OFF state of the basestation device 3. Accordingly, in the OFF state, the base station device3 can perform the CSI measurement in the terminal device 1 even in acase where the transmission of the signal and channel other than thereference is stopped. Since the terminal device 1 can perform the CSImeasurement irrespective of the ON state or the OFF state of the basestation device 3, in a case where the terminal device 1 performs aprocess such as averaging in a time direction in the interferencemeasurement, it is possible to improve the accuracy of the process.

Hereinafter, a specific example of the reference signal for the channelmeasurement and the interference measurement will be described.

In the terminal device 1 for which a predetermined transmission mode isconfigured, the terminal device 1 performs the channel measurement forcalculating the value of the CQI. The value of the CQI is reported in apredetermined subframe, and corresponds to a certain CSI process. Thechannel measurement is performed based on only a non-zero power CSI-RSof the configuration of the CSI-RS resource associated with the CSIprocess. In the CSI process, in a case where the RRC parameter relatedto the ON state and the OFF state is configured for the terminal device1 for which a predetermined transmission mode is configured by thehigher layer, the CSI-RS resource within the subframe in the ON state isused to perform the channel measurement.

In the terminal device 1 for which a predetermined transmission mode isconfigured, the terminal device 1 performs the channel measurement forcalculating the value of the CQI. The value of the CQI is reported in apredetermined subframe, and corresponds to a certain CSI process. Thechannel measurement is performed based on only a non-zero power CSI-RSof the configuration of the CSI-RS resource associated with the CSIprocess. In the CSI process, in a case where the RRC parameter relatedto the ON state and the OFF state is configured for the terminal device1 for which a predetermined transmission mode is configured by thehigher layer, the CSI-RS resource within the subframe in the ON stateand the OFF state is used to perform the channel measurement.

In the terminal device 1 for which a predetermined transmission mode isconfigured, the terminal device 1 performs the interference measurementfor calculating the value of the CQI. The value of the CQI is reportedin a predetermined subframe, and corresponds to a certain CSI process.The interference measurement is performed based on only a zero powerCSI-RS of the configuration of the CSI-IM resource associated with theCSI process. In the CSI process, in a case where the CSI subframe set isconfigured for the terminal device 1 for which a predeterminedtransmission mode is configured by the higher layer, the CSI-IM resourcewithin a subset of the subframe belonging to the CSI reference resourceis used to perform the interference measurement. In the CSI process, ina case where the RRC parameter related to the ON state and the OFF stateis configured for the terminal device 1 for which a predeterminedtransmission mode is configured by the higher layer, the CSI-RS resourcewithin the subframe in the ON state is used to perform the interferencemeasurement.

In the terminal device 1 for which a predetermined transmission mode isconfigured, the terminal device 1 performs the interference measurementfor calculating the value of the CQI. The value of the CQI is reportedin a predetermined subframe, and corresponds to a certain CSI process.The interference measurement is performed based on only the zero powerCSI-RS of the configuration of the CSI-IM resource associated with theCSI process. In the CSI process, in a case where the CSI subframe set isconfigured for the terminal device 1 for which a predeterminedtransmission mode is configured by the higher layer, the CSI-IM resourcewithin the subset of the subframe belonging to the CSI referenceresource is used to perform the interference measurement. In the CSIprocess, in a case where the RRC parameter related to the ON state andthe OFF state is configured for the terminal device 1 for which apredetermined transmission mode is configured by the higher layer, theCSI-RS resource within the subframe in the ON state and the OFF state isused to perform the interference measurement.

In the description of the present embodiment, the RRC parameter relatedto the ON state and the OFF state is configured in the higher layer. Theconfiguration of the RRC parameter related to the ON state and the OFFstate is also referred to as a configuration for the cell stateinformation. The configuration for the cell state information is usedfor the cell state information which is explicitly or implicitlynotified in the physical layer. For example, the configuration for thecell state information includes information required to receive the cellstate information which is explicitly or implicitly notified in thephysical layer. The configuration for the cell state information may beindividually performed for each CSI process. The configuration for thecell state information may be individually performed for each CSIsubframe set.

The CSI process is configured as information specific to the terminaldevice 1 in the higher layer. One or more CSI processes are configuredfor the terminal device 1, and the terminal device 1 performs the CSImeasurement and the CSI reporting based on the configuration of the CSIprocess. For example, in a case where a plurality of CSI processes isconfigured, the terminal device 1 independently reports a plurality ofCSIs based on these CSI processes. Each CSI process includesconfiguration for the cell state information, identity of the CSIprocess, configuration information related to the CSI-RS, configurationinformation related to the CSI-IM, a subframe pattern configured inorder to perform the CSI reporting, configuration information related toperiodic CSI reporting, and/or configuration information related toaperiodic CSI reporting. The configuration for the cell stateinformation may be common to the plurality of CSI processes.

Hereinafter, the details of the CSI reference resource in a certainserving cell will be described.

The CSI reference resource is a resource used by the terminal device 1to perform the CSI measurement. For example, the terminal device 1measures the CSI in a case where the PDSCH is transmitted by using thegroup of downlink physical resource blocks indicated by the CSIreference resource. In a case where the CSI subframe set is configuredin the higher layer, the CSI reference resource belongs to any one ofthe CSI subframe set, and does not belong to both the set of CSIsubframes.

In a frequency direction, the CSI reference resource is defined by thegroup of downlink resource blocks corresponding to the band associatedwith the value of the required CQI.

In a layer direction (space direction), the CSI reference resource isdefined by the RI and the PMI of which conditions are set by therequired CQI. In other words, in the layer direction (space direction),the CSI reference resource is defined by the RI and the PMI assumed orgenerated when the CQI is required.

In a time direction, the CSI reference resource is defined by onepredetermined downlink subframe. Specifically, the CSI referenceresource is defined by a subframe which is positioned before apredetermined number of subframes earlier from the subframe in which theCSI is reported. The predetermined number of subframes that defines theCSI reference resource is determined based on the transmission mode,frame constituting type, the number of CSI processes to be configured,and/or the CSI reporting mode. For example, in a case where one CSIprocess and the periodical CSI reporting mode are configured for theterminal device 1, the predetermined number of subframes that definesthe CSI reference resource is a minimum value of 4 or more among validdownlink subframes.

Hereinafter, the details of the valid downlink subframe will bedescribed.

In a case where a part or all of the following conditions is satisfied,it is considered that the downlink subframe of a certain serving cell isvalid. As one condition, the valid downlink subframe is the subframe inthe ON state in the terminal device 1 for which the RRC parameterrelated to the ON state and the OFF state is configured. As onecondition, the valid downlink subframe is configured as the downlinksubframe in the terminal device 1. As one condition, the valid downlinksubframe is not the multimedia broadcast multicast service singlefrequency network (MBSFN) subframe in a predetermined transmission mode.As one condition, the valid downlink subframe is not included in therange of the measurement gap configured for the terminal device 1. Asone condition, the valid downlink subframe is an element or a part ofthe CSI subframe set linked to the periodical CSI reporting when the CSIsubframe set is configured for the terminal device 1 in the periodicalCSI reporting. As one condition, the valid downlink subframe is anelement or a part of the CSI subframe set linked to the downlinksubframe accompanying by the corresponding CSI request within the DCIformat of the uplink in the aperiodic CSI reporting for the CSI process.In the condition, a predetermined transmission mode, a plurality of CSIprocesses, and a CSI subframe set for the CSI process are configured forthe terminal device 1.

In a case where there is no valid downlink subframe for the CSIreference resource within a certain serving cell, the CSI reporting inthe serving cell is excluded from the uplink subframe. That is, in thecondition in which the valid downlink subframe is the subframe in the ONstate, the terminal device 1 assumes that the subframe in the OFF stateis not the valid downlink subframe.

In a case where the base station device 3 (serving cell) is in the OFFstate, the terminal device 1 may assume that all the subframes includingthe subframe in the previous ON state are not the valid downlinksubframes. That is, in a case where the base station device 3 (servingcell) is in the OFF state, the terminal device 1 assumes that the validdownlink subframe is a predetermined subframe after the subframe in thesubsequent ON state or the subframe notified as being in the ON state.

The terminal device 1 may have a condition in which even the subframe inthe OFF state is the valid downlink subframe. That is, the terminaldevice 1 may determine whether or not the subframe is the valid downlinksubframe irrespective of the subframe in the ON state or the OFF state.

The terminal device 1 may have a condition in which the subframe in theON state and a part of the subframes in the OFF state are the validdownlink subframe. The part of the subframes in the OFF state is apredetermined subframe that is previously defined, a predeterminedsubframe configured so as to be specific to the base station device 3,or a subframe configured so as to be specific to the terminal device 1.For example, the part of the subframes in the subframes in the OFF stateis a subframe between a predetermined subframe and a subframe which ispositioned before a predetermined number of subframes from thepredetermined subframe. For example, the predetermined subframe is asubframe in the ON state or a subframe notified as being in the ONstate. The predetermined subframe is a subframe in which the DCI formatincluding the CSI request is received. The predetermined subframe is asubframe in which the CSI is reported.

Hereinafter, a specific example of the method of notifying of the cellstate (ON state or OFF state) of the base station device 3 will bedescribed.

The base station device 3 performs configuration related to the cellstate information for the terminal device 1 through the RRC signaling.The base station device 3 notifies of the cell state by a predeterminedmethod based on the configuration related to the cell state informationconfigured for the terminal device 1. The cell state information isconfigured for the terminal device 1 from the base station device 3through the RRC signaling. The terminal device 1 recognizes the cellstate by a predetermined method based on the configuration related tothe cell state information configured from the base station device 3.

As the method of notifying of the cell state, there is an explicitmethod or an implicit method. As an example, the cell state isexplicitly notified based on the cell state information notified usingthe DCI transmitted by the PDCCH or the EPDCCH. For example, theterminal device 1 recognizes that the cell is in the ON state in a casewhere the cell state information indicates 1 and the cell is in the OFFstate in a case where the cell state information indicates 0. As anotherexample, the cell state is implicitly notified based on the presence orabsence of the reference signal. The presence or absence of thereference signal is determined by comparing the reception power or thereception level of the reference signal with a predetermined threshold.As another example, the cell state is implicitly notified based on theprocedure or configuration of the DRX. For example, the terminal device1 recognizes that the cell is in the ON state in a non-DRX period andthe cell is in the OFF state in a DRX period. As another example, thecell state is implicitly notified based on the activation ordeactivation of the cell notified by the MAC layer. For example, theterminal device 1 recognizes that the cell is in the ON state in anactivation period of the cell and the cell is in the OFF state in anactivation period of the cell.

As the configuration related to the cell state, information used by theterminal device 1 to recognize the cell state is configured. Forexample, the configuration related to the cell state informationincludes subframe information, information related to the search space,and information related to the RNTI, as information used to receive ormonitor the PDCCH or the EPDCCH in which the cell state information isnotified. The configuration related to the cell state informationincludes information related to the reference signal, virtual cellidentity, a predetermined threshold, and subframe information, asinformation used to recognize the presence or absence of the referencesignal.

Hereinafter, the details of the recognition of the notification of thecell state in the terminal device 1 will be described.

As an example, the recognition of the notification of the cell state inthe terminal device 1 is performed based on the cyclic redundancy check(CRC) added to the PDCCH or the EPDCCH including the DCI for notifyingof the cell state information. For example, in a case where the valueacquired by the cyclic redundancy check is not correct, the terminaldevice 1 determines that the notification of the cell state is not ableto be recognized (detected).

As another example, the recognition of the notification of the cellstate in the terminal device 1 is performed based on whether or not thereception power or reception level of the reference signal is within arange of a predetermined threshold. For example, if a first thresholdand a second threshold greater than the first threshold are defined orconfigured and the reception power or reception level of the referencesignal is within a range from the first threshold to the secondthreshold, the terminal device 1 determines that the notification of thecell state is not able to be recognized (detected). In a case where thereception power or reception level of the reference signal is less thanthe first threshold, the terminal device 1 determines that the cell isin the OFF state. In a case where the reception power or reception levelof the reference signal is greater than the second threshold, theterminal device 1 determines that the cell is in the ON state.

A process (operation) in a case where the terminal device 1 is not ableto recognize (detect) the notification of the cell state will bedescribed.

As an example, in a case where the terminal device 1 is not able torecognize (detect) the notification of the cell state in a certainsubframe, the terminal device 1 assumes that the cell is in the OFFstate until the subframe in which the notification of the next cellstate is performed. That is, the terminal device 1 performs the sameprocess in a case where the OFF state is notified until the subframe inwhich the next cell state is notified.

As an example, in a case where the terminal device 1 is not able torecognize (detect) the notification of the cell state in a certainsubframe, the terminal device 1 assumes that the cell is in the ON stateuntil a subframe in which the notification of the next cell state isperformed. That is, the terminal device 1 performs the same process in acase where the ON state is notified until the subframe in which thenotification of the next cell state is performed.

As an example, in a case where the terminal device 1 is not able torecognize (detect) the detection of the cell state in a certainsubframe, the terminal device 1 assumes that the cell is in a statedifferent from the ON state or the OFF state until the subframe in whichthe next cell state is notified. That is, the terminal device 1 performsa process different from that in a case where the ON state or the OFFstate is notified until the subframe in which the next cell state isnotified.

For example, in a certain subframe in a state different form the ONstate or the OFF state, the terminal device 1 assumes that the downlinksubframe is in the ON state and the uplink subframe is in the OFF state.That is, the terminal device 1 receives or monitors a part or all of thedownlink signals and/or channels, and does not transmit a part or allthe uplink signals and/or channels. For example, the terminal device 1receives the reference signal, monitors the PDCCH and/or monitors theEPDCCH, and does not perform the periodic CSI reporting and/or SRStransmission.

For example, in a subframe in a state different from the ON state or theOFF state, the terminal device 1 assumes that the downlink subframe isin the OFF state and the uplink subframe is in the ON state. That is,the terminal device 1 does not receive or monitor a part or all of thedownlink signals and/or channels, and performs a part or all of theuplink signals and/or channels. For example, the terminal device 1 doesnot receive the reference signal, monitor the PDCCH and/or monitor theEPDCCH, and performs the periodical CSI reporting and/or SRStransmission.

For example, in a subframe in a state different from the ON state or theOFF state, the terminal device 1 monitors a predetermined PDCCH and/orEPDCCH different from that in the ON state. The predetermined PDCCHand/or EPDCCH are monitored in a predetermined search space differentfrom that in the ON state. The CRC scrambled with a predetermined RNTIdifferent that in the ON state is added to the predetermined PDCCHand/or EPDCCH.

Although it has been described above that in a case where the terminaldevice 1 is not able to recognize (detect) the notification of the cellstate in a certain subframe, the terminal device 1 assumes that the cellis in a predetermined state until the subframe in which the next cellstate is notified, the present invention is not limited thereto. Forexample, in a case where the terminal device 1 is not able to recognize(detect) the detection of the cell state in a certain subframe, theterminal device 1 may assume that the cell is in a predetermined stateuntil a subframe in which a cell state indicated by the notification ofthe next cell state is applied. Accordingly, the subframe in which thecell state is notified and the subframe in which the cell stateindicated by this notification is applied may be independently definedor configured.

The various methods, procedures, configurations and/or processesdescribed in the present embodiment may be independent between the Pcelland the pScell in the dual connectivity.

The terminal device 1 according to the above-described embodiment maysupport a function (ul-CoMP) of performing uplink CoMP.

The terminal device 1 according to the above-described embodiment maysupport a function (supportedBandCombination or supportedBandListEUTRA)of performing band combination (CA or non-CA).

The terminal device 1 according to the above-described embodiment maysupport a function (crossCarrierScheduling) of performing cross carrierscheduling.

The terminal device 1 according to the above-described embodiment maysupport a function (multipleTimingAdvance) of multiple timing advances.

The terminal device 1 according to the above-described embodiment maysupport a CSI process function.

The terminal device 1 according to the above-described embodiment maysupport a function of performing communication using cells (a pluralityof cells) of different TDD UL-DL configurations.

The terminal device 1 according to the above-described embodiment maysupport a function of performing eIMTA.

The terminal device 1 according to the above-described embodiment maysupport a function of performing communication using the small cell.

The terminal device 1 according to the above-described embodiment maysupport a function (dual-connectivity) of simultaneously performingcommunication with a plurality of base station devices.

The terminal device 1 according to the above-described embodiment maysupport a function of performing communication using cell (a pluralityof cells) of different frame structure types.

The terminal device 1 according to the above-described embodiment maysupport a function of simultaneously performing transmission andreception.

The terminal device 1 according to the above-described embodiment maysupport a function of receiving the EPDCCH.

The terminal device 1 according to the above-described embodiment maytransmit information (UE-EUTRA-capability or FeatureGroupIndicator)indicating the supported function to the base station device 3.

In the above-described embodiment, the PDCCH subframe may be defined asthe subframe accompanying by EPDCCH (EnhancedPDCCH) or R-PDCCH(Relay-PDCCH) in addition to being defined as the subframe accompanyingby the PDCCH.

From the details of the above-described embodiment, it is possible toimprove transmission efficiency in the wireless communication system inwhich the base station device 3 and the terminal device 1 communicate.

The programs operated in the base station device 3 and the terminaldevice 1 according to the present invention may be programs (causing acomputer to function) for controlling a central processing unit (CPU)such that the functions of the above-described embodiments according tothe present invention are realized. The information treated in thesedevices is temporarily accumulated in a random access memory (RAM) atthe time of the processing, and then is stored in various ROMs such asflash read-only memory (ROM) or hard disk drive (HDD). When necessary,the information is read by the CPU, and is modified or rewritten.

A part of the terminal device 1 and the base station device 3 accordingto the above-described embodiment may be realized as a computer. In thiscase, the program for realizing the control function may be recorded ina computer-readable recording medium, and the program recorded in therecoding medium may be realized by being read and executed in a computersystem.

It is assumed that the “computer system” mentioned herein is a computersystem built into the terminal device 1 or the base station device 3,and includes OS or hardware such as peripheral devices. The“computer-readable recording medium” refers to a portable medium such asa flexible disk, a magneto-optical disk, a ROM or a CD-ROM, and astorage device such as a hard disk built into the computer system.

The “computer-readable recording medium” may include a medium thatdynamically retains programs for a short period of time such as acommunication line in a case where programs are transmitted via anetwork such as the Internet or a communication circuit such as atelephone line, and a medium that retains programs for a regular periodof time such as a volatile memory within the computer system which is aserver or a client in this case. The program may be used to realize apart of the above-described functions, or may be realized by acombination of the above-described functions and programs alreadyrecorded in the computer system.

The base station device 3 according to the above-described embodimentmay be realized as an aggregate (device group) constituted by aplurality of devices. Each of the devices constituting the device groupmay include a part or all of the functions or functional blocks of thebase station device 3 according to the above-described embodiment. Thedevice group may have the general functions or functional blocks of thebase station device 3. The terminal device 1 according to theabove-described embodiment may communicate with the base station device3 as the aggregate.

The base station device 3 according to the above-described embodimentmay be Evolved Universal Terrestrial Radio Access Network (EUTRAN). Thebase station device 3 according to the above-described embodiment mayhave a part or all of the functions of the higher node for the eNodeB.

A part or all of the terminal device 1 and the base station device 3according to the above-described embodiment may be typically realized asLSI which is an integrated circuit, or may be realized as a chipset. Thefunctional blocks of the terminal device 1 and the base station device 3may be individually realized as a chip, or a part or all thereof may berealized as a chip by being integrated. The method of realizing thedevices or functional blocks as the integrated circuit is not limited tothe LSI, and a dedicated circuit or a general-purpose processor may beused. In a case where a technology of realizing the devices orfunctional blocks as the integrated circuit has appeared instead of theLSI due to the advance of semiconductor technology, it is possible touse an integrated circuit produced using this technology.

Although it has been described in the embodiment that the terminaldevice is used as an example of the terminal device or the communicationdevice, the present invention is not limited thereto. The presentinvention may also be applied to terminal devices or communicationdevices of stationary or non-movable electronic devices which areinstalled indoors or outdoors, such as AV devices, kitchen devices,cleaning and washing machines, air conditioners, office devices, vendingmachines, and other home appliances.

CONCLUSION

(1) In order to achieve the above-described object, the presentinvention provides the following means. That is, a terminal deviceaccording to the present embodiment is a terminal device including: adetection unit that detects a signal or a channel; and a channelmeasurement unit that measures CSI based on a CSI reference resourcedefined by one valid downlink subframe. In a case where the signal orthe channel is detected in a subframe, it is expected that the subframeis the valid downlink subframe.

(2) In the terminal device according to the present embodiment, thesignal or the channel is detected by a reception power of a resource towhich the signal or the channel is allocated.

(3) In the terminal device according to the present embodiment, thesignal is DRS.

(4) In the terminal device according to the present embodiment, thesignal is CRS.

(5) In the terminal device according to the present embodiment, thesignal is CSI-RS.

(6) In the terminal device according to the present embodiment, thechannel is PDCCH.

(7) In the terminal device according to the present embodiment, thechannel is PDSCH.

(8) A communication method according to the present embodiment is acommunication method of a terminal device. The method includes: a stepof detecting a signal or a channel; and a step of measuring CSI based ona CSI reference resource defined by one valid downlink subframe. In acase where the signal or the channel is detected in a subframe, it isexpected that the subframe is the valid downlink subframe.

(9) An integrated circuit according to the present embodiment is anintegrated circuit mounted in a terminal device. The integrated circuitis adapted to have: a function of detecting a signal or a channel; and afunction of measuring CSI based on a CSI reference resource defined byone valid downlink subframe. In a case where the signal or the channelis detected in a subframe, it is expected that the subframe is the validdownlink subframe.

The embodiments of the present invention have been described withreference to the drawings. However, the detailed structure is notlimited to the above-described embodiments, and the present inventionalso includes a change in the design within the gist of the invention.The present invention may be variously changed without departing fromthe claims, and embodiments acquired by appropriately combiningtechnical means disclosed in different embodiments are included in thetechnical range of the present invention. The elements described in therespective embodiments and structures acquired by replacing the elementsthat exhibit the same effects are included therein.

REFERENCE SIGNS LIST

-   -   1 (1A, 1B, 1C) Terminal device    -   3 Base station device    -   101 Higher layer processing unit    -   103 Control unit    -   105 Reception unit    -   107 Transmission unit    -   301 Higher layer processing unit    -   303 Control unit    -   305 Reception unit    -   307 Transmission unit    -   1011 Radio resource control unit    -   1013 Subframe configuration unit    -   1015 Scheduling information interpretation unit    -   1017 CSI report control unit    -   3011 Radio resource control unit    -   3013 Subframe configuration unit    -   3015 Scheduling unit    -   3017 CSI report control unit    -   1301 Measurement unit    -   13011 Layer 1 filtering unit    -   13012 Layer 3 filtering unit    -   13013 Report criteria evaluation unit

1-9. (canceled)
 10. A user equipment comprising: a measurement unit configured to measure channel state information (CSI) based on a valid downlink subframe, wherein a downlink subframe is considered not to be the valid downlink subframe if the downlink subframe is used for neither a transmission of a downlink physical channel nor a transmission of a downlink physical signal.
 11. The user equipment according to claim 10, wherein the downlink subframe is considered to be the valid downlink subframe if the downlink subframe is used for the transmission of the downlink physical channel or the transmission of the downlink physical signal.
 12. The user equipment according to claim 10 comprising: receiver configured to detect a physical downlink control channel (PDCCH), wherein the downlink subframe is considered to be the valid downlink subframe if the PDCCH indicates that the downlink subframe is used for the transmission of the downlink physical channel or the transmission of the downlink physical signal.
 13. The user equipment according to claim 10, wherein the downlink subframe is available for the transmission of the downlink physical channel or the transmission of the downlink physical signal.
 14. The user equipment according to claim 10, wherein the downlink subframe is available for neither a transmission of an uplink physical channel nor a transmission of an uplink physical signal.
 15. A communication method of a user equipment, comprising: a measuring step of measuring channel state information (CSI) based on a valid downlink subframe, wherein a downlink subframe is considered not to be the valid downlink subframe if the downlink subframe is used for neither a transmission of a downlink physical channel nor a transmission of a downlink physical signal.
 16. An integrated circuit mounted in a user equipment, the integrated circuit adapted to have: a function of measuring channel state information (CSI) based on a valid downlink subframe, wherein a downlink subframe is considered not to be the valid downlink subframe if the downlink subframe is used for neither a transmission of a downlink physical channel nor a transmission of a downlink physical signal. 